I haven't really thought about the question as you've asked it but I've noticed a lot of new ideas lately. For example I'm reading "The Chosen" by Roberto Pinto which has a great deal of new and interesting facets - mostly based around a rigid and brutal caste system that delineates the races. I'm only about a third of the way through as it is a difficult read. Not for the prose itself, it is actually very well written, but so far only depressing, sad and cruel things have happened and I'm finding it hard to slog through. I mean to finish it though because it is unique and well written.
I like different views, such as the one in "The Golden Key", a collaboration between a couple of authors whose names escape me right now. In this story the magic element comes through art, specifically painting.
Many of the 'themes' will always stay the same, I believe, because readers look for certain things from recreational reading. We look for something we can't get from our everyday lives; adventure, morality, nobility, personal triumphs, companionship, fun...at least these are what I enjoy. We also like to learn new things, identify with the characters, feel emotions along with them, etc. Again, these are my own personal feelings and others might look for other things.
As far as a lot of fantasy being 'similar' to each other, I don't really follow that view. I've found very few that are so similar that reading both is a waste of time. Of course many elements will be similar but each story and each character has their own uniqueness. Even down to similar elements as dragons and elves - each author brings their own vision. I've read about evil elves, dragons can be sentient or more beastlike, wizards can be humble and wise, miserable and cranky, villainous and greedy - so even cliches can be given new life if seen through a different author's vision. So I don't really think that fantasy 'needs' anything. Except maybe more authors
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