A lot of EFAs cannot get back into the fight anywhere near as quickly as WFA. I'd much prefer there being more risk and punishment for being heavily wounded on both sides.
These polls are fun aren't they!
Currently, for example: 2 Comets vs a Tiger and Panther. The Comets will just win. Even if the engagement is 'equal' and both take damage. The UKF faction can get those tanks up to speed x2 as fast as the Wehr player can. Meaning overall, you can just push and push and push. This is completely disregarding all the cheap insta smoke repair abilities and the fact that the RE's are just better in every single way. Jeez UKF are incredible OP atm, soz, have to reinforce it - back on topic:
USF can repair from their tanks to begin with.
OKW is tricky(?). Because like Wehr, they generally can not get as many tanks out as Allied factions. So if they also get nerfed I'd want the sturm repair upgrade to remain. Wehr pioneers vet 2 has to remain too for the same reason.
This is opposed to buffing EFA to WFA levels as I personally prefer a more sluggish engagement involving all units. Not just tank on tank late game action.
(You could also make another discussion on what should be done for the stupid movement penalties on the older factions.)