Dean was alright in the novel, mostly because there was a little more actual work with his character. I didn't really like him until a later arc, though. Hopefully it's well handled in the manga. If it is he might be a little more likable in general. The problem is that the manga decided to speed up her becoming attracted to him and removed a lot of details. That sort of thing is kind of common in wn manga adaptations, honestly. The content of the wn is relatively short and the bulk of it is difficult to really express in a visual format. It also doesn't help that we haven't seen his motivations in the manga yet. Those make him a far more rounded character overall, since currently he's basically just the facade he's attempting to impart. A little too perfect, if you will. As much as Dean isn't really the most developed character in the story, he at least has a little bit more dimension to him in the wn by this point.