It's a great little piece of film.Perhaps if Ten had said it, yeah, it would've been weird. It actually seems pretty normal for Eleven, however. I think by now he's come to terms with being the last of his kind, after that firm reminder in the End of Time that it was for the best.
Best line in the whole trailer:
Voice: Fear me, I've killed hundreds of Time Lords. Doctor: Fear ME. I killed them all.
Although remarkably flippant of the Doctor, considering his past feelings about the issue.