Just my two pence, but the main improvemenr for me about RTR was the change in kill speeds, for one reason and one reason only: It actually brings some tactics back into the game. With vanilla, it seems that any 1v1 is decided within seconds of contact: a few deaths; one unit routs. With the slightly slower attack rates, it means you can actually use units to pin people down so you can flank and your formation and battle line becomes more important. I think people see 'slower kill rates'' and automatically think it's going to make the game less exciting. If you've tried it and still don't like it (and I'm sure that's the case with many people on this thread), fair enough, but if you haven't tried it yet, don't let the words put you off.

Slower kill rates means more scope for maneuvering, more exciting battles and less of those epic 6000+ men five-seconds-of-fighting-followed-by-ten-minutes-of-mopping-up-routers encounters.

The other changes (missile troops are less effective, some units are missing, more territories, more buildings) are again matters of taste, but to be honest they don't seem to have a huge effect on the game.