I think people on this forum underestimate how the UI has turned off casual UT players, players that don't go online much if ever.
These players spend a lot of time changing maps, changing gametypes, changing mutator combinations, changing bot levels, trying new mods...
To the point, in any given evening after a long day of work, many casual players spend quite a bit of time within the menus playing around with different bot & mutator setups.
In UT, and do a lesser degree UT2004, performing these functions was quick, seamless and even fun.
But to perform these adjustments in UT3 requires an impossibly tedious and slow collection of chores involving backtracking and waiting for various menus to load.
I know many of you like to lean on the argument that UT3 got it right where it counts -- in the core gameplay -- and that you just briefly pass through the UI to get to the part that counts. And you know what? I personally agree with you.
But in the age of Facebook and iPhones, user interfaces count. Most people -- read: non-hardcore players -- expect an application or a piece of entertainment to provide more than its isolated core purpose.
Not only is the UT3 UI just plain bad in its own right, but it's a bad era to blow it with the user interface and the community building tools.