Hey, Hawkeye's one of my top 3 or 4 Marvel characters. But an A-lister he ain't, otherwise you have a pretty liberal grading scale

As for whether or not he's an essential Avenger to display, well, that's extremely subjective, and I wouldn't say that folks aren't "true fans" who don't have him on the shelf (though I will). I think
Hulk is definitely NOT an essential Avenger, since he lasted less than 2 issues. I think the real "essential" Avengers are the other founders plus Cap. In my mind, Hawkeye is in that 2nd tier list with his other early teammates Scarlet Witch and Quicksilver, Wonder Man, Vision, and to a lesser extent guys like Beast and Black Panther.