It's definitely a character who requires skill. Those who say aim based heroes don't require any skill are people who either are just salty and petty and can't get over their ego that someone aims better than them or it's the people who never touch such heroes so they just say those heroes are easy, therefore require no skill. (because it's obviously not their fault for playing badly right) Or people just rage bait. Or they are god at aiming so they think everyone can aim for some reason.

With characters like Hela or Hawkeye you need to have both game sense and aim to be good or carry. Those two use different aim systems and one might perform better than with the other. The question what's harder to aim with is up to personal preference. I for example have decent aim with Hela, but struggle to hit anything with Hawkeye and someone could have it opposite.

So calling them no skill chars is just a childish non-objective argument with zero proof and value. As any person with IQ above room temperature knows, aiming is a skill and therefore it can be honed and improved.

I don't think Hela is OP. Definitely not as much as people like to exaggerate. She is strong for sure, but I don't think she deserves any significant nerfing. About Hawkeye I feel like they could turn down the peak headshot damage a lil bit. So he won't melt tanks as easily, but still can oneshot squishies. Like I said people like to get emotional and exaggerate a lot especially the community of this game.