Personally I'd like it if they stripped back a lot of the things like medics and engineers, given how unrealistic either would be in a WW1 scenario. Charging across muddy craters with bullets whizzing past would be amazing, but they probably won't go that route because stalemates and balance issues (MGs OP).
Tanks should be incredibly rare, rather than the disposable jets you get in the current gen. If they actually put in the effort to recreate a proper WW1 style battlefield (as in the place not the game) then I think it could be amazing. In reality though, I feel like it will play very much like all the recent BF games.
Also I assume that bright green was supposed to be chlorine gas. Super unrealistic, but I suppose otherwise the average gamers would complain. Wish they'd tone down the colour of it, but ah well.