I seriously can't believe they'll kill off Banner.
without Banner, there is no "Hulk". this Red "Hulk" is just a knock off, with a good line in quips (well, occasionally).
the leaping with mjolnir thing is a bit too silly, why not just grab Thor and leap into space, then grab mjolnir off him - that way you avoid making stupid "reasons".
I'm more or less certain that Hulk (Banner) is gonna come back and beat Red to a pulp... it'll be another Onslaught Hulk kind of performance, where he really cranks up the beats, reaching deeper into his infinite reserves ...