Who said anything about superpowers? Having an uncanny knack for something isn't the same thing as getting abducted by aliens or bitten by a radioactive bug or **** like that. I just think that Joss wanted to do a slight riff on Hawkeye's name to give it a little more meaning and backstory, and I think it's pretty darn cool that he did so. As for getting powers from the Tesseract: that's pretty much a given. The Tesseract *does* give you powers. It's a god-cube or a wish-cube.