First of all, I love Heather Tom as Katie Logan and liked how the brought her back to the show as being unlike Brooke and Donna. She was the logical, rational Logan. I loved it when she warned Thorne about Donna and therfore saving him. A Thorne/Katie pairing would have been good but for some reason the writers have turned her into her sisters which is ashame. She redeem herself a bit by reminding Brooke that Taylor is Jack's mother.
Maybe they will go back and make Katie who she was before the rewrite. As for her and Nick, not sure about that.