Haven't we had this thread already?
Karpyshyn is worth mentioning but for the title of absolute worst he's edged out by the likes of Traviss, Denning and the TCW crew.
Traviss is responsible for some of the worst things to grace the EU but at least has the RC books to her name and the TCW lot have a few good episodes despite some of the trash they spew out. On the other hand, I can't think of anything Denning's written that's particularly good, and he's got his fair share of rubbish as well. So he's probably the worst on average for me.
Originally posted by Zenwolf
What's Grevious backstory now? Think I missed that.
I think it's that he was jealous of the Jedi and thus chose the improvements. It's pretty crappy. Nothing compared to his tragic Legends story, where he was interesting. I'm not sure if he was jealous of the Jedi (I just heard that) but I know for sure he chose to become that cyborg/robot (he said this in the TCW episode where Kit and Nahdar fight him in his lair) which is pretty dumb IMO.