Look, I don't like him either. You think I wanted Black Widow to be the one who couldn't be revived in Avengers: Endgame? If anything I wish Hawkeye could have died twice – or better yet, a million times while trying to cut a bargain with Dormammu. Unlike Dormammu, I would never get tired of that. Unfortunately, if we were all caught with Hawkeye somehow being away from the Avengers for all eternity, they would cease to be an effective fighting force.
I won't even get into how one man took down cartels, terrorists, and gangsters worldwide.
1. The Avengers are 7-0 with Hawkeye
This is probably the most important reason. As one aptly-named Redditor pointed out, while some of you might believe this is coincidence or luck, they are also 0-4 in battle without Hawkeye. Why did Thanos win in Infinity War? I'm not saying it wasn't because Hawkeye wasn't there but I'm also not ruling it out.
Black Panther is wearing a Vibranium suit and Hawkeye is fighting him with a stick while wearing a t-shirt.
2. Hawkeye is fundamentally better than every other Avenger
Is Hawkeye a demi-god? No. Does he have billions of dollars? No. Sorcery? Super Serum? A metal body? No, no, no. Hawkeye is a guy, just some dude, who sees really, really well. Let's see if skinny Steve Rogers can get punched in the face by Thanos all day. We've already seen what happens when Tony Stark is wearing Tom Ford and not Iron Man. Even though he basically just wears clothes and shoots a bow and arrow (albeit with some trick arrows), he's still flying around in space, fighting aliens, and taking on killer robots.
At least you know one of them can help with the mortgage.
3. Hawkeye is the glue that keeps the Avengers together
Where did the Avengers go when their chips were down? Hawkeye's house. Where even his wife had to point out what a freaking mess they all were. He recruited Black Widow and turned arguably the most powerful Avenger – Scarlet Witch – into a real sorcerer just by pointing out that he was fighting an army of robots with a bow and arrow because that is his job.
Hawkeye: 1, Avengers: 0
4. The Avengers are lost without Hawkeye
Literally. The one time Hawkeye was actually playing for the other team, he just completely kicked the crap out of them. Agent Coulson got killed and two of the more powerful Avengers were spread into the wind. He's lucky Natasha hit him in the head with a railing because there's no way they'd have beaten Loki – or even come together as a team – without Hawkeye. Hawkeye became the Avengers command and control center, turning a bunch of riff-raff into a coordinated fighting force.
Even when pitting Hawkeye against Wave II Avengers, there's still no comparison. He tases Scarlet Witch and gets the upper hand against Quicksilver.
"You exist because I let you."
5. At least two of the Avengers are alive because Hawkeye let them live
One of the first clues we get to Black Widow and Hawkeye's shared past is that Hawkeye was supposed to kill her and decided to recruit her for S.H.I.E.L.D instead. When Thor was powerless in New Mexico, Agent Coulson decided to send another agent in to stop the God of Thunder, who was just mowing down his S.H.I.E.L.D. agents. Hawkeye, instead of ending Thor, Hawkeye let him live.
Bonus: Hawkeye does sh*t other Avengers barely pull off, if at all
In Endgame, Spider-Man in a powered suit is overcome by Thanos' forces. Captain Marvel in all her glory eventually gets taken down. Meanwhile, Hawkeye is running through tunnels and rubble away from crawling doom carrying the Infinity Gauntlet, simply handing it off to the Black Panther.
For the record, he's also the only Avenger to hold an Infinity Stone and not whine about it endlessly. After seeing Hawkeye throw Cap's shield, I'm pretty sure he was also pretending he couldn't pick up Thor's hammer.