These are my thoughts on two specific abilities from the Gunner and Grenadier classes and potential rebalance ideas:
1. Grenadier, Corporal rank: Steady Weapon (Ends turn, but raises aim by 20 on the next shot. Interrupted by damage.)
While Steady Weapon was certainly important in the original LW, I don't think this ability is comparable to the other two options: an extra grenade, or bonus armor and 66% explosive resistance (Especially when Sharpshooter gets steady for free). To make this ability viable, I think it needs to be changed to a blue action instead of ending the turn: this would give the Grenadier the ability to aim better with his rifle, providing a viable alternative that is on-par with his other abilities once he has run out of grenades. Furthermore, if Steady were a blue move it would also synergize with Suppression on reaction shots, making this rifleman Grenadier build more viable--especially since Grenadier base aim is so atrocious. If this changes the sharpshooter ability too, I think it would be okay since a sharp could only use his pistol after steadying. As for snap shot sharps, well, that might be a different story.

2. Gunner, Corporal rank: Steady Hands (Gain +10 aim and +10 crit chance if you did not move last turn)
I get that the idea behind this ability is that an MG gunner is likely to stay in place, especially if he is suppressing; however, unlike a Sharpshooter, a Gunner often needs to move in order to keep suppressing, since that's the ideal way to use this tree. However, this is generally only useful in the event that you set overwatch traps spanning multiple turns (not really useful for timed missions, only good if you have disabled timers), but often in X2 we have situations where cover gets destroyed, or you get flanked. This ability is extremely useful on long-range Sharpshooters, who often stay in the same spot for most of the mission, but for a Gunner, it just doesn't feel that great compared to holo-targeting (which applies on suppress) or shredder, which is probably still arguably the best ability at this tier. To make it better, I propose that this ability be changed to be the same bonus, but also give Squadsight out to 3-5 tiles past normal, much like the MGs in LW. This would make this ability make more sense and really give the feeling of a proper MG gunner, I feel.

There are other solutions of course, but these are two perks I felt were really weak tier-for-tier. I don't know if they'll be changed but I thought I would give my feedback.