I disagree. He just needed to be written right. I mean all characters on the same power level as him (he's actually above Captain America in the comics) have much better things to do in the Marvel Extended Universe. Widow, Punisher, Daredevil.
If you write a character poorly, that's what's going to happen. People were absolutely jacked about Hawkeye after his Thor cameo. Then The Avengers comes and he's basically just a cop with a bow.
True story was that Hawkeye was a huge part of the original script but when Whedon came in he cut a bunch of Hawkeye stuff, turned him bad, and gave Widow more screen time.
Just an example - my best friends daughter's favourite character in the TV Show Earth's Mightiest Heroes is Hawkeye and Wasp. In the movies, she didn't like Hawkeye at all because he's "boring." And he is, I agree with her.
He was awesome in his 3 minutes of Civil War screen time because THAT'S HAWKEYE. A sarcastic yet loyal guy who will stand up for what he believes regardless of danger. Him chirping Tony at the end brought back memories of him going face to face with Cap.
Hawkeye has marketing value. He's kinda like the Ninja Turtles right now. He was written poorly, stripped of his colours, costume, and personality, and given an awful adaptation of himself to portray. Things that are marketable sometimes lose value because they're done wrong.. Just like the Turtles films. I'm still convinced that the 2nd Turtles movie does great if their designs don't scare children, lol.
Its like changing skin colour of a character to try to appease to demographics. Fantastic Four was dead before arrival because they made Human Torch African-American.
The best thing to do for Marvel and Hawkeye is to finish up his current story in Avengers 3 and 4. And then reboot him with a run based off the Matt Fraction comic on their Network or Netflix. Good way to introduce Bishop as well.
As a Hawkeye fan its just frustrating. From poor writing to not even being in Old Man Logan because Marvel sold their properties, lol.
I finally though Civil War was the breaking point. I thought the Russo's could revive the character (the scene that was cut from Winter Soldier with Hawkeye because of Renner not being able to get away from another film - was just as good as Civil War).
Maybe the Russo's have something really good planned. I guess we will see. I'm just not hopeful with him being stripped from all marketing.
I mean, I can't miss... I'm on a team with super-humans. And one god, in case you've forgotten. Even you... well, you climb walls really well. The training is the only thing that makes me special. And if I'm not special, then none of this is worth it. I gave up a lot for this life. I could have been happy with Mockingbir-- Bobbi. We could have had a good, simple life. But I wanted to play with the big boys. And if I miss, it means I'm just another dude with a bow. It means I've been fooling myself this whole time. And that's why I never miss. 
