I have to agree with this. The original Medieval probably had the best gameplay of all the TW games from what I remember. But the graphics do seem outdated. If only the soldiers were more than just sprites... And also, I think the vast provinces on the campaign map make it too easy to expand your empire. I like to role play somewhat, and play within reasonable historical parameters. In order to do so, a lot of the time I would have to remain inactive for hundreds of turns! It feels silly when your Polish army is crusading in France and England each campaign...
EDIT: I've also grown accustomed to the damn RTS camera of RTW and its successors. I think the TW camera is superior, but I'd have to spend a lot of time to get used to the old version again!