I never get why, when it comes to Marvel and DC movies, the popularity of the character among the readers should be so important.
Most people who watch movies don't give a crap about how long a character has been used in comics and how popular they are.
Striker, Cloud 9, Starlord, Blue Marvel: it's all the same: who?! With a good team and a good marketing, any of them can be as much a hit as Iron Man.