-They changed almost every voice in the game with a new voice. Mostly the same but some effects were dropped and such (example: the Terran base attack alert no longer has the alarm sound at the beginning).
-Some interface changes were made
-The AI for all levels now work (try playing Insane Terran using Protoss. You'll find it quite impossible).
I think that's the gist of it. I'd image those would take up a lot of space.
[Edited by Neo7, 7/10/2010 10:06:46 AM]