Mini-crits instead of crits while ubered
-20% movement speed while ubered
-20% max overheal

No, this is better you noobs:
100% Crit recharge rate
50% More damage
70% equip speed
Bonks everyone who gets contact with its fire

♥♥♥♥♥♥♥ this one is fantastic Do
-100 damage
-No crits
-70 health for the player

heh

When crit charge is activated, death-mark applied to pyro so he must use flanking even with crits.
Also, after activating there should be less overheal from medic.

since phlog pyros always need more protection, they do a lot of damage but cant take it

Same stats, but:
+ 25% bullet damage vulnerabillity
-20 max hp
(as another user said,) 35% less healing from medics

I would also reccomend adding a buff to offset the nerfs, but still making the phlog less annoying such as

-minicrits/__% more damage against players who are drenched in liquid,

Therefore stopping people who want to run the scorch shot or flare with the phlog, because the liquid would extinguish them, or, if you want them to switch off the phlog more

+50% melee deploy speed/firing speed on kill for 3 seconds