Yeah, I don't think it was necessary at all, if they wanted to change things then that would have been fine, it would have been nicer if they spread it out a bit more though (like the new Daleks as the climax of the series instead of a few episodes in for example).
It's probably my favourite part of the entire series, it just gets so funny to me =D Yeah you're right, it would be kinda samey, usually repition is only really effective if it's been ages since you did it last so I can't imagine them doing it again any time soon.
Hmm, maybe he is a bit more evil, I'm not sure as I haven't seen much so maybe it took a bit longer for those qualities to come out, from what I've seen though most of his character is just doing a bad David Tennant impression :/ Which I can understand why as he was huge part of the series, but I loved the change between the ninth and tenth Doctor so it would have been nice to see them be a bit more adventurous (and they could have made him ginger, although they're probably saving that for the last doctor if they're ever gonna do it)