Quake 3 hitsound, FrankenHUD, all of Chaofanatic's Texture Improvement Project particles (I highly recommend these, they make the game look so much better), and of course the Pop It Don't Drop It taunt.
The maps themselves aren't broken, the update just made it so that if you're playing on a server that runs any of those maps you'll be unable to download them from the server and won't be able to play on them unless you've already downloaded them or download them manually, which is a really dumb bug that'll hopefully be fixed quickly.