If Gaiman still has MM stories to tell, he should tell them in MM's own universe. If you've never read the Moore/Gaiman Eclipse run (which was heavily edited by Marvel in their reprint release), MM completely remakes Earth into a quasi-utopian society where everyone is on equal footing and has free access to everything. No way would the heroes of the 616 allow that to happen on their Earth. If memory serves, King Thor already tried that once anyway. And yes,we definitely don't need anymore "Superman wannabe's" because those stories have been told so many times now they just repeat themselves.