I, personally, would be pretty darn pleased with Jedi Knight on the Infernal Machine version of the engine. I forgot it used the Sith engine...
I like the way that game looks. I think it always looks sleeker when a game isn't trying to look completely realistic. Indy3d tread the cartoony/realistic borderline pretty well, I thought.
Anyhow, if that were the case, the only thing that'd need changing would be the movement system, and a first-person view...everything else could be ported, I suppose. Oh...right, and then there's the whole multiplayer part...