I’ve gotten a lot of these, and the answer to all of them is pretty much the same: while none of these sorts of trades is ever going to come to pass, suggestions like this one go beyond fun fan fantasy speculation into the realm of insanity. So I really can’t even take them seriously. I do think that the Marvel characters work best as a part of the Marvel Universe, and DC and other characters work best as parts of their respective universes, especially when you’re talking about the most prominent characters.