So, say the Federation and the other power players in the Star Trek Universe try to wage war against the Marvel Universe. How well do they do? I know they wouldn't beat the big guns like Galactus, the Celestials, the abstracts, etc. But what about Shiar? What about the Kree? What about the phalanx? How does this fight go down?
You said Wanda can't erase Raven, but you never said she couldn't change her past by altering reality. An enraged Wanda at full House of M levels would rewrite history so that Raven was never trained in magic and is as weak as a normal human. She then summons a Kree armada to fire rockets at Raven's head.
@CitizenBane: I thought he was an imp from a different dimension (one with fractions?) and Mxy's equal in magic?
There was a Superman/Batman story where Mxy told the Joker that the latter had retained a small piece of Mxy even after he'd been stripped of his Emperor Joker powers, and he later caused Joker to spit out that piece, which turned out to be Bat-Mite.
Well, that's just one of multiple origins. Originally, he was just another 5th Dimensional imp like Mxy, then they changed that and gave him the Emperor Joker origin, and then they changed it again and made him a figment of Batman's imagination. Honestly, I don't think continuity really matters in the DCU. Next week he'll probably have a completely different origin.