TS2 was a good console game, but that just shows how far console FPS's are behind PC games. I don't think there's a lot of elements from TS2 that could really add to gameplay, in fact, I'm having hard time imagining a TS2 mod that didn't take the game backwards.
Just about the only thing that really sticks out about TS compaired to PC games is the mix of "sci-fi" and "realistic" weapons. Unfortunately, the "realistic" weapons were nothing more than a slew of generic unrealistic bullet-hose machinegun clones, and the sci-fi weapons were all just cheap knock-offs of weapons from Quake, Unreal, and Halo.
There really isn't anything else from TS worth bringing into UT. The aiming system sucks and wouldn't work in a PC game, and you can't even jump. The variety of gametypes was nice, but wouldn't really offer anything new to UT, which allready has a ton of modes. Great console FPS's don't really translate into great PC FPS's.