A UC2 port for UT2 would be awesome! Though, I would suggest a few optional server-side gameplay tweaks like:
UT3-style Stinger alt fire; because UC2's homing alt-fire is unskilled, UT3's stinger rules, and there is no Pulse/Link Gun in UC2.
Removeable Burst Mode on the Sniper Rifle; because having to use the scope to access the normal headshot-capable single shot was lame, and while an amusing novelty, we're glad the UC2 SR's burst mode didn't make it to future Unreal titles.
Reflected shots go where you're aiming, instead of auto-aiming back at the opponent; for the sake of skill.