I love Disney with all my heart, always have, always will. I REALLY hope Marvel stays at Universal. It just seems to fit better, to me. And honestly, I'm worried Disney wouldn't do it right. As it's been pointed out, at this point they've been pretty much dropping the ball with Star Wars, and it's likely the same would happen to Marvel.
Marvel "done right" is already happening, at a park that has a whole area dedicated to it already. I've also seen all the reports that Universal is, in fact, planning to expand/improve on their Marvel park presence, and I'm hoping for that.
Like it's been mentioned, Disney has a huge, competitive with Marvel, mostly male-focused IP to work with in Star Wars. They've been teasing about big new SW things coming, and already have a huge success with SWW. Why would they suddenly put all that on the back burner to take over another IP and develop that just because they make the movies now? I'd really rather see them start to really work with SW before getting into any other new thing.