I voted for comic-book/superhero movie. IMO, that's the ideal tone they should be going for. I don't agree with all this grittiness = better movie. Not all the time. If every film was like The Dark Knight, summer at the cinema would become quite a depressing affair. Although, I do want Eternia to feel lived-in, not like a perfect fairy-tale kingdom. I would like them to go down the same route that Peter Jackson went down with Middle-Earth. It was still a fantastical land, but it felt real, too.
In terms of the actual mood and tone of the film I was thinking something along the lines of Iron-Man. It had its lighter moments, it had plenty of action and adventure, but when it wanted to it could get pretty dark and intense (particularly towards the end). Also, I think Willow would be another good example of the kind of tone I think the new movie should have.