No phase will be cosmic central or Earth-based, Feige does not look at the phases like that, as he said himself. It is a "one-off" in the sense that it's not related to the Avenger, which is why they're making the film in the first place...they want the cosmic to be a thing on its own (with the exception of big villains the Avengers are known for fighting of course). Guardians may lead to other cosmic movie being launched like the Inhumans, but that doesn't mean what the phases will or will not be "cosmic" or "Earth-based", whether it's well received or not.
As for this thing with Drax, Marvel should leave him the way he is from the comics. He's that way for a reason. He has one mission and one mission only, and that is to kill Thanos. It will most likely work within the movie anyway. This doesn't mean he is a shallow character, though. He's very thoughtful and philosophical, he's just quiet and intimidating at the time. When he does talk it's for good reason. The character is fine that way.
