Vanilla Rangers are already in a great state, but for purposes of scouting are completely outclassed by Reapers. This mod somewhat remedies the situation, and buffs some of the least used abilities.

I consider Blademaster, Bladestorm and Implacable to be must-have abilities for a melee Ranger, so I put all of them into the Assault specialization.

The following perk pairs share their themes, so I put them on same ranks:

• Implacable and Run and Gun - powerful perks that have to do with deep diving and action economy.
  
• Bladestorm and Untouchable - theme of being hard to get.
  
• Deep Cover and Conceal share - theme of cowering behind cover to hide from enemies.

Overall, you get two clearly different specializations/playstyles: Assault is all about offensive use of the sword. Deep Cover can help get into the position under fire, but Conceal is also a viable pick on the same rank.

Meanwhile, Scout is still the poor man's Reaper, but with its own identity of waiting for the right moment, and then bashing the door in and getting empowered by Shadowstrike, but only several times per mission.

Overall, Assault is obviously still much stronger, but there's only so much I can do without completely overhauling the class.

• Ability tree rearranged.
  
• Phantom - buff: now additionally reduces detection range in concealment by 40%.
  
• Shadowstrike - buff: now actually applies its bonus while concealed instead of against enemies that can't see the Ranger. The bonus is now also provided for the entire turn the concealment was broken, and is now applied to melee attacks in a transparent manner. In vanilla, Shadowstrike can be applied if your initial movement tile is not visible to the target, which is a potentially interesting mechanic, but I don't believe is the intention behind the ability. It should be more streamlined now.
  
• Untouchable - QoL: added a flyover and a buff chevron when the Untouchable bonus is gained.
  
• Rapid Fire - buff: now has a 3 turn cooldown (down from 4). Cooldown is now mentioned in the extended description. Now it will match the cooldown of Run and Gun.

Sharpshooters are functionally fine in vanilla for the most part, but their perk progression is awful. With my rework, key perks are given earlier, and there's a clear gameplay loop of proccing Death From Above, and then using that action point on Hunker Down to boost your accuracy with Aim next turn. I also put Fan Fire earlier in the tree and on the same rank as Deadeye, as both are high damage single target abilities, and Faceoff and Serial are also on the same rank now, which makes way more sense to me than the vanilla layout.

Both Aim and Death From Above now have proper interactions with pistol abilities, which should make the Sniper spec a bit more versatile

• Ability tree rearranged.
  
• Squadsight - buff/fix: removed hidden crit chance penalty.
  
• Return Fire - buff: now ignores enemy cover defense bonus and can trigger any number of times.
  
• Deadeye - buff/consistency: aim penalty is now flat -20 Aim and damage boost now applies to the total attack's damage.
  
• Death From Above - redesign: now works with pistols, but triggers once per turn. No more free Serial with Darklance, sorry.
  
• Aim - buff: aim bonus now applies to all attacks made this turn. Aim is a much more powerful ability now, and can be highly desirable to a soldier of any class who is able to fire multiple shots per turn through whatever means.
  
• Serial - nerf: added -20 Crit penalty after each kill. Vanilla description mentions a crit chance penalty, but it's not implemented in vanilla. This nerf should bring Serial a bit closer in line with Reaper.
  
• Fan Fire - nerf/consistency: now ends turn. There's just really no reason for Fan Fire not to be a turn-ending ability, even with Quickdraw. It's way too powerful for that.

Grenadiers are changed the least by the rework. The biggest changes are buffs to Suppression and Demolition, the rest are mostly bugfixes.

• Blast Padding - bugfix: now applies to environmental damage.
  
• Demolition - buff: now a guaranteed hit and applies Holo Targeting. Utility abilities shouldn't be able to miss, in my opinion, especially considering that depending on situation, it may end up doing absolutely nothing even on a hit.
  
• Suppression - buff: now ignores cover defense bonus. New triggering rules: it preemptively triggers on attacks, but suppressed unit gets one tile of movement to attempt to break line of sight, which will remove the suppression. Bugfix: units with Shadowstep and other similar abilities can also safely break suppression by moving. Key problem with vanilla Suppression is that it seems to have minimal effects on enemy AI, and they either just fire through it, being completely unharmed by bullets whizzing past them, or just run it, and the Suppression shot just misses most of the time, due to the double whammy of enemy sometimes getting Cover bonuses while running and the reaction fire Aim penalties. New triggering rules will also give some counterplay to Suppression.
  
• Chain Shot - buff: aim penalty moved from the first shot to the second one. It's a pretty arbitrary change. I just always hated how vanilla Chain Shot with Holo Targeting gives you like 60% hit chance on the first shot and 90% on the second one. Now it'll be a perfect ying-yang of both shots having same hit chance.
  
• Saturation Fire - now more reliable at destroying cover. The description doesn't tell you this explicitly, but Saturation Fire uses the same logic as Demolition, and can destroy cover only if there's a unit behind it, which doesn't really make sense for a sweeping machinegun burst. With the rework, Saturation Fire will behave more like Collateral Damage from Enemy Within, and can be used to punch through walls even if there's nobody behind them.
  
• Rupture - consistency fix: no longer usable while Disoriented.
  
• Volatile Mix - bugfix: no longer applies to Flashbang (only base game flashbang is patched).

Mostly bugfixes and consistency improvements. Notably, all Protocol abilities no longer end turn.

• Combat Protocol - buff: no longer ends turn. This should bring up Specialists' offensive capabilities somewhat.
  
• Revival Protocol - charges changed to 1/2/3.
  
• Haywire Protocol - buff: no longer ends turn. It's a pretty huge buff to potentially a very powerful ability, but keep in mind it's pretty unreliable even in vanilla.
  
• Field Medic - fix: now grants bonus charges regardless of the slot where the Medikit is equipped. E.g. so that Field Medic can interact with Medikits in Medicine Pouch correctly.
  
  
• Scanning Protocol - buff/QoL: unlocked camera while targeting. Charges changed to 1/2/3.
  
• Covering Fire - buff: now ignores cover defense bonus.In vanilla, Covering Fire is a pretty lame perk that is often actively harmful, this is a gameplay buff and it just makes sense that you would ignore cover, since enemy needs to step out of it to attack.
  
• Threat Assessment - buff/bugfix: now properly works for Templars. Now also ignores cover defense bonus, but the Covering Fire effect is removed after taking one Overwatch shot.
  
• Ever Vigilant - not changed by this mod, but using Reliable Ever Vigilant is recommended.
  
• Capacitor Discharge - buff/consistency: damage now ignores armor.

Vanilla Reapers are already excellent, so this rework mostly just fills the holes in their ability tree and buffs some of the weaker abilities.

• Ability tree rearranged.
  
• Soul Harvest - buff/consistency: increased Crit Chance boost per kill from 5 to 10 and max Crit Chance boost from 20 to 40. Now can be triggered by Claymores, and apply to any attack that can crit, not just Vektor. This lets you reach 100% crit at full stacks against flanked enemies if you use either upgraded Superior Laser Sight or Talon Ammo.
  
• Sting - buff: now a guaranteed crit and has a 2 turn cooldown instead of 1 use per mission.
  A necessary buff in the world of so many other ways for Reapers to keep concealed while shooting. Should also let you leverage Vektor's high crit damage a bit more often.
  
• Blood Trail - consistency: bonus damage now also applies to bleeding units, though there's no way to apply bleeding in this mod.
  
• Infiltration (GTS perk) - buff: hacking bonus increased from 25 to 75. Maybe now you'll have a reason to hack objectives with a Reaper.
  
• Squadsight, Tactical Rigging - now included into the main ability tree.
  
• New ability: Improvised Silencer - Remove the chance of being revealed on the first shot after entering Shadow.
  
• New ability: Shadow Rising - Shadow gains an additional charge.
  
• New Ability: Death Dealer - Critical shots against a flanked target while in Shadow will deal double critical damage. This sounds absolutely bonkers, but keep in mind the target has to be flanked, which means you can't benefit from this ability against unflankable enemies.

Skirmishers are considered by most to be the weakest faction hero class. Many of their abilities are either useless or broken, and many can be used only once per mission. Their Bullpups also have poor scaling. So the result is that they have essentially only one viable build, and even that falls off towards the late game significantly. This mod addresses all of that.

• Ability tree rearranged.
  
• Justice - bugfix: fixed a visual bug that makes the enemy float in the air if it's pulled into high cover and then killed.
  
• Wrath and Justice - cosmetic improvement: now have a special execution animation when killing humanoid enemies.
  
• Reckoning - buff/consistency: no longer has a cooldown, but dash attacks (outside blue move range) consume more action points. Now has a proper icon. In vanilla, Reckoning is a 1 AP ability you can use to dash across the map on a 5 turn cooldown. It's just weird.
  
• Reflex - buff: now triggers once per turn instead of once per mission, and displays a debuff while it's on cooldown.
  
• Total Combat - buff: now also grants a Grenade-only slot.
  
• Zero In - buff/consistency: now works with melee attacks and grants +20 Crit per attack (up from +10).
  
• Whiplash - redesign: now has a 5 turn cooldown instead of one use per mission. Damage now scales with Ripjack tier, pierces armor and can crit.
  
• Interrupt - buff: now grants two actions and has a 3 turn cooldown instead of one use per mission. Multiple units can Interrupt together now.
  
• Combat Presence - buff: can now be used during Interrupt and Battlelord.
  
• Full Throttle - buff: Mobility bonus increased from 2 to 4 and now Full Throttle also reduces Grapple's current cooldown on kills.
  
• Waylay - buff: now allows reaction attacks to crit.
  
• Battlelord - buff/bugfix: fixed bug that prevented it from triggering more than once. Multiple units can use Battlelord together now. Battlelord and Interrupt cannot be used at the same time. Now has 4 turn cooldown instead of 1 use per mission.
  
• Return Fire - buff: now a part of the main ability tree. Now triggers ignores enemy's Cover defense and can trigger multiple times, as long as Bullpup has ammo.
  
• Lightning Reflexes, Tactical Rigging - now included into the main ability tree.
  
• Parkour (GTS perk) - buff: using Grapple now grants a move-only action.
  
• Ripjacks - buff/consistency: now have 10% innate chance to crit, same as swords.
  
• Bullpups - buff: mag tier crit damage increased to 2, beam tier base damage increased from 6-7 to 7-8.
  
• New ability: Forward Operator -> immediately gain an extra action when a new group of enemies is revealed. Triggers once per turn.

A lot of people consider Templars without Bladestorm and Reaper to be second class citizens, so now they have both in their main tree. Many abilities were tweaked to make playstyles other than hurr-durr-Rend-24-7 viable.

• Ability tree rearranged.
  
• Rend - new icon.
  
• Volt - buff: no longer ends turn.
  
• Parry - bugfix/consistency: now is a defensive ability that cannot be interrupted.
  
• Aftershock - bugfix/nerf: no longer stacks with itself.
  
• Overcharge - buff: since it applies only to non-lethal Rend attacks, chance has been increased to 100%.
  
• Amplify - buff/consistency: now consistently increases total attack damage. In vanilla, Amplify could provide different damage increase when stacked with other effects that increase target damage by a flat amount depending on effect application order.
  
• Deflect and Reflect - buff: now have separate rolls, and both rolls happen before Parry. Reflected attack now uses Templar's Aim for hit chance instead of a flat chance and ignores target's cover Defense bonus.
  
• Exchange and Invert - buff/bugfix: Focus cost removed. Can be activated with regular and Momentum action points. Cooldown increased from 1 turn to 2. Exchange can no longer target turrets.
  
• Pillar - redesign: now a free action. Cast range limited to 18 tiles. Can no longer summon on tiles adjacent to units to avoid a bug with Pillar not granting cover in that circumstance. Remaining duration now displayed on the Templar as a buff.
  
• Stun Strike - buff: now is a guaranteed hit and can be interrupted, and instead of disorientation stuns the target. Knockback is still not guaranteed.
  
• Void Conduit - buff/consistency: new icon. Can be interrupted. Visualization hang resolved. Instead of dealing 3 damage when used and draining 2 HP per action at the start of enemy turn, it drains 2 HP when used, and then 2 HP every turn at the start of the player's turn. Now correctly disables the target for the number of turns equal to Templar's Focus when cast. Cooldown increased to 3 turns.
  
• Ghost - buff: no longer ends turn, and has a 5 turn cooldown instead of 1 use per mission. Ghost now always has the same base HP as the Templar that summoned it. The confusing mechanic that made its HP scale with Focus is removed.
  
• Bladestorm - renamed to "Zeal" and is always present in the ability tree (no longer an XCOM row random perk). New icon.
  
• Reaper - always present in the ability tree (no longer an XCOM row random perk).

• Repair - buff/bugfix: amount repaired now scales with BIT tier. Cures acid and other stuff normally healed by Medikit, though SPARK is immune to it anyway.
  
• Bombard - buff/consistency: now shreds 1/2/3 armor.
  
• Sacrifice - bugfix: integrated Sacrifice Targeting Fix.

Made a pass over all abilities used by the vanilla classes to make sure they can be interrupted by abilities like Covering Fire when it makes sense. This includes Psi Operatives too, which are otherwise unaffected by this mod.

• If it's an offensive ability, it can be interrupted, even if it's a free action.
  
• Neutral abilities can be interrupted if they're not a free action.
  
• Defensive abilities cannot be interrupted. This includes Overwatch.
  
• Exception from this are Specialist's GREMLIN abilities - none of them can be interrupted. Previously, only Capacitor Discharge was interruptible.

• Faction heroes now will have a much larger variety of XCOM abilities.
  
• Cross-class abilities for regular soldiers are also somewhat expanded.