Like Carmack said in one interview, The Q3 engine is pretty much the best that you can reasonably have for a fast competitive twitch shooter (which most of the Quake games were).
There is a good reason why Doom3 and Quake4 multiplayer never caught on. Most of the extra cool stuff gets disabled by any experienced player, and this is exactly the demographic UrT is targeting.
If you look at successful online competitive shooters, most of them use very old engines, often updated with small, necessary improvements and eye-candy. You don't need per-pixel lighting in a competitive online match, in fact, you don't want it.
Besides: UrT is a really really old Q3 mod. I played it almost 10 years ago.
All my hope of having linux open-source game progress has just demolished, urt was my favoutire game and one of the things I liked was it being opensource, and I felt very excited by all of the new games that would use the new improvements to the ioquake3 engine. I hope something like what happens with nexuiz and xonotic happens here too, we're losign big games, this is not good.