Originally Posted by DrCosmic
I think this is the most solid and most likely.
Thanos returns, having acquired nearly all of the Infinity Gems, and proceeds to come and dismantle Earth. He keeps dismantling it and it's looking like the Avengers aren't coming together. Hulk is corrupted by Thanos, Stark has a Virus, Thor is missing, Cap's been shot, and some of these new guys aren't exactly the team type. Eventually though, the Avengers pull themselves up out of the mire, and come together, Hulk fights off Thanos' influence, Stark reboots himself, Thor returns from the dead, Cap wakes up from his coma and rallies the rest of the team which at that point consists of: Captain America, Bucky!Cap, Falcon, Iron Man, War Machine, Thor, Sif & The Warrior's Three, Hulk, at least one Ant-Man, Black Panther, Dr. Strange, Captain Marvel, Black Widow, Hawkeye, a couple agents from the TV Show (Mockingbird and Quake?), and depending on Avengers 2/Ant-Man's story, Vision. They fall like flies from Thanos' might until one gets through to Thanos, to his gauntlet specifically and breaks it so it roars out of control and implodes him. Any one of them could be that hero. Perhaps multiple endings, perhaps, if the reality/time gem is in effect, multiple realities occur at once to stop him.
Man, I like doin this stuff too much. I would do Planet Hulk with Pixar as a CGI film in continuity with the MCU, lol.