Mark Griskey - Star Wars KOTOR 2 OST - The Final Battle

This guy would definitely be a worthy successor to John Williams.

They actually scored music for this game? Wow, Lucasarts like never scores music for their games, they just reuse music from the movies

Yeah, there are actually a few games that have some original music in them, like this and the first KOTOR have almost 100% original music (save the Star Wars theme), and there are others where only, say, half the music is original (Republic Commando, Bounty Hunter, Empire At War, and the Force Unleashed Games).

Successor? No one can replace John Williams.

Hans Zimmer could. In fact, I believe that Hans Zimmer is a better composer than Williams anyways. See, Williams is really good, but his stuff is actually quite repetitive and usually marches or some variation of. Hans Zimmer on the other hand has such a wide spectrum of sounds and styles yet still that glimmer of Zimmer if you know what to listen for (usually Enio Morricone style sounds/riffs/background tracks)

True, Zimmer is better. Also True about the Ennio Morricone sound. I'd actually never thought about that, but it does fit.

It helps to have read a few things too. See one of Zimmer's all time favourite movie composers is Morricone, so he likes to pay tribute whenever he can. His two major ones is a track on the POTC3 soundtrack and one on the Rango soundtrack, both of which are essentially variations of Harmonica's theme from Once Upon a Time in the West