Well Earth would be screwed.
So let's say (for the sake of the planet) that none of the villains have powers either. What do I think would become of the team?
Natasha Romanoff: Scholar
I know she doesn't technically have powers in the MCU. But if things had gone a little differently I like to believe the Red Room would never have existed at all, and she would have been able to live her life. Comfortably in academia, writing critical essays about Russian horror films.
Steve Rogers: Tiny Soldier
Okay so fingers crossed that pneumonia doesn't knock him out at the ripe old age of 25. I think he would have actually found a way to serve in the war: With the MFAA. You might remember them as The Monuments Men (thanks to that George Clooney movie). Members of the program were generally not fit for combat: Most of them were older, and their specialties were in art history or curation. He would have been a perfect addition to the team, and we all know he wasn't going to take 'no' for an answer.
Bruce Banner: Happy.
That is all.
To assemble or not to assemble?
I definitely like thinking about these non-powered versions of everyone getting together. Maybe I'll share the rest of the team in a little bit! I'd like to see what everyone else says.