It certainly doesn't break the game. Indeed most of the interesting action for me goes on in the early campaign, when the armies are nothing but hordes of drab spearmen. It just makes me a little sad to think that my expensive computer is working so very hard animating all those little soldiers, only for it to wasted on ugly units for most of the game. I kind of feel that if I'm going to win, I might as well look good doing it. The chivalric knights and the musketeers know what I'm talking about.

I definitely agree about the AI challenge in MTW. In almost every campaign, I found that one of the AI factions would match my expansion and turn into a rival superpower, setting the game up for a huge late-game showdown. RTW simulated this somewhat with the Roman civil war, but M2TW doesn't really have anything like this except the Mongols and Timurids.

All that said, the fact remains that these are things I miss, implying that I have moved on to M2TW. I find it is one of those games that, no matter how much I enjoy griping about the little things that annoy me, I can't seem to stop playing.