Yukimura:
Neither is wrong for wanting what they want, but someone will have to compromise if either of them is going to get what they want from eachother. From what we've seen I suspect Itou is more motivated to take actions that might lead to sex then Katsura is motivated to take actions that might lead to romance, but at least they are both trying. What throws a wrench in the works is the fact that Itou's desire for sex doesn't hinge as much on Katsura specifically, and Sekai is shaping up to be a much more responsive partner. To be fully realistic, Katsura's desire for romance shouldn't necessarily hinge on Itou either, but the whole 'mysterious train watcher' element is part of the romance and thus he does fit more into her scenario then she does into his. There's also the fact that there's not really any other viable males in the story anyway.