1) The console UI is annoying to navigate through, and impossible to navigate through once I've had a couple of drinks.
2) I lost 2 hours of stats a few weeks ago due to the stats servers going down. Not sure how often they go down because I don't play it enough.
3) Most servers seem empty, especially on DM/TDM.
4) For some reason, running/jumping around seems very slow and sluggish, and less accurate than it used to be.
5) SP mode was far too short.
6) Nalicity (the best site for custom UT maps) went down and lost all UT3 data, along with a lot of 99 and 2k4 maps. It's been months and they still haven't pulled their fingers out of their bums.
7) Hardly any decent custom player/bot models and skins out there at the moment, it seems the customisation community died along with UT3.