There's nothing there to dislike nor like, he's just there. Oda could have touched on something more emotional and personal with the character if Kidd died but obviously that was never going to happen. As it stands he's just another Zoro-esque character without the deeper moments or focus. At some point when you've consumed enough media characters like Killer have no appeal anymore, like I need something more to like a character, he can't just "be cool". I do like the fact that Kidds crew now all laugh along with Killer to make him feel normal, that's actually quite heartfelt and does slightly flesh out the crews dynamic.