Highly doubt any of that would happen. Trem is good the way it is. Even if we use the new engines all that graphic and detail - while pretty cool - seem a little too unnecessary. It's been nearly half a year ago when I heard trem 1.2 was coming out "soon" and its still not out. Imagine even if they work on the new engines, by the time it's done there will probably be a "super realistic engine with better resolution than real life" that will come out. Then people will say trem should switch to that and it will be a neverending cycle.
Improve things as they are now. Adding more units, buildings, guns, maps, abilities, gameplay, and content in general should be the priority.
As for improving graphics somebody could do that for the existing quake 3 engine. Games like Crysis are too much of a hassle anyways since you have to have the top of the line comp to run it, which will alienate many players.