By far one of the most common criticisms of Hawkeye is that, compared to all the superpowered members on the Avengers, he's just a tad redundant. Why these same people are perfectly content to see Black Widow on the team but not Clint is in itself pretty bizarre, but then you also have to bear in mind that no one really tends to bat an eyelid when the Dark Knight - himself just a man - lines up alongside Superman, Green Lantern and Wonder Woman on the Justice League.
It just doesn't really make a whole lot of sense, and this isn't even the worst reasoning behind why Hawkeye apparently can't cut the cloth alongside Earth's Mightiest Heroes. Some even postulate that it just doesn't make any sense for someone who's just really good with a bow and arrow to be on the Avengers, as if it's some kind of affront to suspending disbelief.
To that, there's only one thing to say: these are comic books.
They're not meant to be real, and though there is an argument for ensuring that people are immersed in a given experience, if they're content with seeing a man wield lightning, and a scientist who turns into a ginormous Jekyll and Hyde-esque monster on screen, then it's time to admit that the argument that Hawkeye is too outlandish for the Avengers just doesn't hold any water.