UT 2K3 came out at a time when most people didn't have the hardware to play it, either. UT2K4 came out when everyone caught up hardware-wise. It wouldn't surprise me if they did a re-release when UT3's requirements are a bit more mainstream. My x1950 Pro runs its acceptably well, but some of the lighting effects cause lag on certain areas. For DM games, I need my framerate to be extremely smooth, as I don't like to lose battles because my video card lagged in the middle of a firefight.
I loved Vehicle CTF, though. Maybe they just should have held off release until after the onslaught of good games had settled. Say, in March or April of this year. Timing is everything.