The problem with eye-candy sporting pregenerated maps becomes apparent when you play, say, 1866: After a short while, you really do get tired of fighting on the same ten or fifteen strips of land for the hundredth time. You end up always using the same manoeuvres, and you always know where to go to and what to expect. Also, it becomes visually insulting to see the exact same sight over and over.
Maybe for some gimmick mod that you play once or twice, such maps are fine and useful, or for multiplayer, in which the opponents use more variable tactics...but for obsessively playing in SP mode - and obsession is the hallmark of the TEATRC player - it has to be procedurally generated.
I mean, I don't know about how much time other TEATRCians have spent playing the mod, but if the battlefields in TEATRC weren't random, I'd have seen the same pre-made maps for thousands of times by now. So unless there's a way of including interesting pieces of scenery within the procedurally generated maps...oh, hold on. You're just talking about flatness.
Personally, I don't mind some big mountains, but more often than not the steepness of the mountainsides and the jaggedness of the hills is simply ridiculous and unplayable. Certainly unenjoyable!