so far i've had mixed feelings from starcraft 2 sounds. i hate the new zealot and zergling sounds. the new dragoon, marine and reaver sounds do not impress me. however the new nuke, ghost, nydus worm, and black hole sound was amazing!
i think it'd be a bit too detailed...whoever heard of panting units in a strategy game?
Sounds give personality to a character/unit. I havnt memorised how the sounds compare between sc1 and sc2, but generally i loved the sc2 gameplay demo.
Zealots have a lot more fluid movement but sounds are slighyly more electronic. Their attack sound is more of a slash (higher pitch), whereas previously it was a thuding noise (lower pitch). Its not that bad, I think you will get used to it.