Thanos will make the other Marvel villains look puny. The Infinity Gauntlet basically makes him a god.
Sounds like they're building an unbeatable villain except for one tiny achilles heel. Give me a clever plan any day.
My hope is that the Marvel Cinematic Universe is being smart about using all these characters. In that last scene you can fully take in how many superheroes we have to play with. Everyone is acting like the next film is going to have ALL of them PLUS the Guardians of the Galaxy and ones like Doctor Strange who haven't been introduced yet. That can't leave much room for Iron Man to have internal conflict.
I don't believe Marvel plans to.
I think they're building the universe that doesn't need all of the characters all of the time. With each adventure there will be major and minor players. (Budgets and box office expectations will be adjusted accordingly.) This was there isn't an absolute need to lock the cast into contracts followed by a need to cram them into the film because they're contractually obliged to. If they can't get Downey Jr. to play Iron Man for a couple of scenes, give the scenes to Bruce Banner or Star Lord. This is why the next Captain America can be a major event, like Avengers, but you can also round up all the sidekicks from the last scene of the film and make them the stars of a more modest film, with a few Captain America scenes giving them their orders.
Also, Black Widow is to the MCU what McBain is the The Simpsons. I say this in agreement with everyone else who doesn't greenlight films for Marvel. She deserves her own movie, and I believe it would be very successful. While watching her vision in Avengers 2, I had the thought that perhaps when ScarJo has made her last Marvel appearance, you can edit all of her scenes together and it will tell the story of Natasha Romanoff.