I think Marvin would have rattled and unnerved Moorer for awhile, but sooner or later Moorer's sharpshooting would connect hard on Johnson's balding skull, and Michael would have finished him off, kind of like the Mustafa fight.
Moorer. Johnson seemed to always come up a little short against top fighters with equal or better talent. Though Marvin did face better fighters at LtHvy than Moorer did.
Marvin liked to engage and Moorer hit to hard. If Marvin doesnt break Moorers at times fragile fighting spirit then he can catch Marvin and stop him in what should be a great fight. A rea l gut check for Moorer though as Marvin brings it like all hell.