Demoman ability -
Demomen equiping the Chargin' Targe can have the stats that still come with the shield (admins may buff/nerf as they see fit), although the shield does not get it's charging ability.
Heavy ability -
With the heavy's GRU, perhaps it can still have its old speed back, for the cost of a lower set health, e.g:Heavy has 300 health, heavy equips GRU, heavy now has 250 health. this does not mean that once the heavy is using the GRU as his current weapon he loses 50 health, I mean that when its in his loadout slots (when one equips it on the loadout screen/backpack screen), his max health will be 250.
Engineer ability -
An engineer with the Southern Hospitality can activate a rage/boost where he gets a 100 hp boost for 20 seconds, and a speed boost. I was kinda hoping that the speed boost would be as fast as GRU heavies (if engineers actually are faster, then can it be faster than that? W/E, its up to you guys if you want the engi boost to make him faster than GRU heavies, if this ability even gets "published")To activate it - Taunt key/G