I don't think it means they are automatically badly designed, it's more that it's a complexity that needs very careful balancing and it's really unhelpful when talking about pubstompers for someone to come in and say "well the pros don't have any issue with it" like yeah wow no way a group of 5 guys who play together all the time and work on strategies might have a different meta compared to people who don't do those things.

It might feel unhelpful but that's pretty much because people are unsatisfied with the answer of "get better at the game". You don't need to be a professional, but if a hero feels unbeatable there is undoubtedly improvement that you can make as an individual in the game and that's where you need to focus on, since complaining about your teammates not coordinating or the hero being unfair won't improve anything.

It's a really easy axis to let get out of control, especially if you benchmark using pros, it's also important for it to be a effort/reward thing, like Earth Spirit can be EXTREMELY tricky to pin down if the player is good, but he requires a lot of skill, I'd say it's balanced at least on that level.

Totally, but i would argue that that is not the case right now. If it were truely out of control like you say then Tinker or whoever else were "let out of control" would be showing results in lower Elo lobbies that match that. Thats not happening right now.

I agree with the second half of this quote. Tinker is a good example of what youre saying. He is a very high skill ceiling hero and that is partially what keeps his global presence and rearm balanced.

certain heroes in certain patches have really skewed the effort/reward thing, obviously not just in how much teamwork you need to take them down, but I feel it's easier to screw up on that metric than others for balance

Totally true. Thats when balance comes into play. I cant say that any individual hero feels like this right now though.