So we could assume BP will be introduced in his own movie eventually?
I apologize for all of the hitherto ranting, but I feel it's (just about) justified because it's not like we have an infinite amount of time and resources to do justice to the classic, vintage group of Avengers.
Will there be "civil wars" amongst the fandom over the selection of any new (to the MCU, that is) Avengers? I'd say there already are.
The best way to proceed IMO is a conservative guideline: the classic/most popular Avengers first, then we can think of something else. Because, if this didn't matter or wasn't a priority, then the likes of Demolition Man would be in with a chance...
Squirrel Girl would be badass, though (and she can take down Thanos - there's your problem solved, TA2/3).