Can anyone do a brief rundown of what changes to expect in UU2 for those who have played UU1? (Of course, conversely for those who played just the sequel)
As you can read in the Mobygames summary posted above, gameplay wise there are no changes. Personally, I found the second episode a lot better because it's directly related to the "standard" Ultima storyline. It also sports a variety of environments, which make for a more immersive and diverse experience. And it's quite a hard game on the top of it: like I wrote in my general review, personally it's my favourite Ultima, together with the seventh episode (especially Serpent Isle).
Ah... I never got into the main series, so it might not matter to me much. I didn't have a hard time with UU1, but then again, I only got through 5 or 6 floors. Just charge, strike, backpedal over and over won any and every fight, really... But it was unusually fun for some reason.