The sound was definitely an improvement. I mean, Secret of Monkey Island with voices? Yes please! And the music was also an improvement over the EGA/VGA versions, even though the old pc sound music had its charm.
I guess I'm not alone when I say I hated Guybrush's design, because he looked too much like an idiot. I mean sure, Guybrush is not Einstein, but his facial expression looked really stupid.
Adding that hair to that killed the design for me. But that's something I could overlook.
The handdrawn BGs were really nice IMO, although they look better from a distance and a little rushed when you look closer. But I like how sometimes there were little holes in the BGs through which you could see the original pixels.
The controls were OK, but I have a feeling that this xboxified interface was even more difficult for beginners to use than the original verb-and-item bar. If anything, I think a MI3-ish interface would have been good for this game. That might have come in the way of the safe-puzzle though, and I'm sure there were a few others that made a difference between different actions.
Oh well, it's not easy to come up with a good solution for everyone.
Overall, I do not regret that I bought it (for half the price on TLAP-Day), and if it was for the voices and experiencing the awesomeness that is SMI in a new way.