it was pretty much determined publically that soule wouldnt be coming back for this. As well, it was said by one of the devs on these forums, I believe, that obsidian had no control over that aspect of developing - LA is responsible for this switch.
I wouldn't assume that this new guy is worse than soule, either, but he hasn't had a chance toprove himself. Not everyone thinks soule is all that, either.
This new guy probably has his chance of a lifetime to prove himself to a bigger audience, so he's probably under some stress right now. Who knows, maybe we got a new 'great' composer here.
But i can't still get rid of the mental image of a Lucasarts CEO saying "Hey, that Jeremy Soule guy can do some nice music, but he's too expensive and we need to get this project as cost-effective as possible. Take that new guy instead, he's cheap and we're talking STAR WARS here, anyone can make a decent soundtrack out that!"