How about nope ! WW1 theme already ruined a game i liked(BattleField), i would like to keep playing COH.
Battlefield 1 is not set in world war 1.
All in all, it would be great but there is too much folks who will not accept anything other than western front 44-45 for a setting. CoH could work in ww1 and it could work nearly flawlessly for 39-41 ww2 but noone is going to do it, because you cannot release a ww2 game that does not feature USA and those late Wehrmacht vehicles that make so many people fap over them.