Post-NJO. Then again, one can argue that even THAT was creepy with the whole 'Vong-Torture Cult' aspect.
Characters I can't stand? Off the top of my head, I can remember that I've never liked Atris, Dooku, any of the Yuuzhan Vong, and I've never really been a fan of Callista
Droma was bad. But I admit that maybe it was too soon. X-7 was a total bore. Hethrir and Waru, however, are hands down the most awful characters in the entire SW library. I think that's largely because they're in the most awful book in the entire SW library.
I'd have to say Alema Rar. Just kill the b***h already! Callista. I don't know why, I just never liked her. No chemistry between her and Luke at all. Vergere -- I still think she was just a wannabe Sith. And maybe she saved Mara with her tears, but the way she abused Jacen she seriously screwed him up, and lead him to the Dark Side. Stupid B***h. Bria. HATE HATE HATE!!! HATE!!!! Allston fixes everything. I hate Borsk, but he's the kind of character you love to hate, so I don't know if he counts. You're supposed to hate him.
I agree on the Borsk bit. He's the bully you like to watch lose. He's a good dislike as it were. Bror Jace. Disliked him too. But then, I'm a Corran fan. EDIT: I thought you said Bossk, not Borsk! No no no no no! Borsk is never a good dislike for me! Him and Natasi Daala can burn!
Y'know, I'm kinda sad Allston never got to write Borsk. He could have included him in the Wraith books but didn't. That would have been interesting.
Off the top of my head... Zayne Carth - Whiny with the worst voice actor ever. Atton Rand Bao-Dur - Not so much him but his whispering voice actor. I-5 - ridiculous droid sue Quinlan Vos Thrawn - Not so much Thrawn, but Zahn's obsession with him. Ahsoka Starkiller Mara Jade - Just terrible in every way and Zahn's complete ignorance of her. Kyp Durron - In the JAT, he's fine in the NJO. Callista Akanah - Probably my most hated character. Jacen Solo
Seconding Zahn's worship of his pet OC, the blue Grand Admiral. I might be able to appreciate Thrawn if it were not shoved in my face how much I'm supposed to appreciate his brilliance. Post season 2 Ahsoka, for the same reason. Filoni is trying to make her into some sort of goddess, and it's not working. Rush Clovis. "Oh Padme, my dear..." Yeah, just STFU already. Jorus C'baoth. That's no moon, that's Jedi Master ***hole's ego. Any clone of any dead character. Any character resurrected in any form other than Force ghost.
I don't see how Thrawn takes over whatever he appears in. All I ever see with Thrawn is an intriguing villain that I appreciate.