The problem is that its near impossible to make 80 diffirent heroes very closely balanced at both the low and high skill level. In fighting games the same issues already shows up with a half roster. And in tekken (which has a much bigger ability variance compared to street fighter) you already notice that certain characters are more often picked by lesser skilled players, and some by higher skilled.
1 thing however that fighting games can do, which hots cant is make perfect 1v1 countering options. If an enemy has faster abilities, you get compensated by still having quick defensive capabilities, and some quick initiators to ‘stun’ the enemy and start your chain.
In 5v5 that simply doesnt work that easily.
Thats why comparing hots to fighting games is a bad thing to do, they are too diffirent. And thats why hots balance is much harder aswel.
And as a result, they try to balance acros multiple levels, and sometimes just change for the sake of change (changes the meta on all levels). Its not perfect, but it does the job well enough.
1 thing that however is popular is making the hero have a very high skill ceiling by introducing micromanagement into easy heroes. These easy heroes would otherwise often end up being OP on higher skill levels, or always remain useless. By making the skill floor low enough, but increase its ceiling massively, you can sometimes end up with a player who managed to master the hero.
And that sometimes breaks heroes for certain players by making the hero too difficult to simply have fun with it. And since most players actualy fall in the lesser skilled group, its heavily disliked.
After all, it makes it feel like the game is getting balanced towards only highly skilled competetive players. While for them it doesnt matter at all if a hero is useless, they will automaticly play by that meta anyway, and in most cases enjoy it aswel.
Thats why most heroes should be balanced towards gold’ish style, with varieties towards silver and platinum, and only nerf heroes when they are blatantly OP on master+ levels. Sure, they might be somewhat stronger than others, and by that be a default pick. But thats not an issue. For this you can still introduce talent based hardcounters on heroes that are generaly UP to potentialy boost them as counter option.
But power creep is actualy a problem in 5v5 game types, it forces the game around instant kills and makes heroes that arent capable to assist in it quite useless. Its much better to increase the time to kill so all heroes are much better capable of joining in into the combo. This adds a better balance for a team game.
There is a reason why TF2 is still popular, for a game that feels quite quick, the TTK values are quite high. Sure, in an optimal case its still near instant (1s), but in plenty of fights, it can easily take a constant barrage of damage for 20+ seconds (and thats excluding the uber which can add another 8 seconds).
Its best to make optimizing TTK values as hard as possible. Otherwise its going to cause 1 thing: “Players will optimize fun out of the game”.
In this case, they optimize the meta in such way 80% of the heroes becomes near useless. If they cant optimize that aspect, they have to become creative again. And the more options you make, the more ways to optimize they get. At some point, it becomes near impossible to optimize the fun out of the game. Thats when a game has proven to work properly.
Even in a basic shooter like CS where headshots are the best optimizing you get, you can always optimize a counter tactic towards the most popular tactic. It becomes “rock paper scissors” state which is a random generator game and therefor cant be optimized.