I've come up with this idea, i know that Relic won't abandon DLC stuff like commanders so new system must have them.
Let's take german docs for example - they will have 3 Doctrines that can't be replaced in lobby (for example, defensive, blitzkrieg and Terror) and each doctrine has 3 trees and each tree will have 3 abilities to unlock. These trees will be called commanders (DLC COMMANDERS ALSO) which can be changed in Lobby like it is now. So each doctrine can be made with it's own way, abilities unlocked like it was in CoH1 and i bet we would get many many more abilities and units.
http://imageshack.us/f/32/gkhm.png/
I think that this photo would say more than 1000 words
![:( :(](/images/Smileys/sad.gif)