Do people expect Riot to find the "perfect balance"? (WARNING: opinions incoming)
If so, they shouldn't, because I don't think even Riot is looking for it.
There's a reason Riot always changes the game with more patches, and its not because they're looking for that perfect "sweet spot" where everything is balanced and every champ is equally viable in their intended roles. No, the reason they change their game is simply because they want it to change, because its a living game that changes over time, and that's what keeps the game fresh.
If they ever found that "perfect balance" where everyone would supposedly be happy, the game would flourish for a bit, and then die soon after. Why is that? Because at that point there'd be no where else to go. The game would become stagnant, because there'd be no objective reason why you would want to use one champ over another when they both perform equally well in the same role. Sure youd maybe one day want to choose Zed over Akali as your go-to assassin, and the next day vice versa, but sooner or later people would lose interest, as they wouldn't be able to experience the satisfaction of mastering a Champion and being rewarded for doing so, because why would you bother mastering a hard champ when you could just play an easy champ and do equally well all the time? (Liking the design of the character themselves I think would only last so long before even that wore off.)
I think thats what it would boil down to, satisfaction. A lot can be said for the satisfaction of learning the ins and outs of a champion completely, mastering them, knowing their limits, what they can and cant do at any given time, and knowing when you can capitalize on a certain situation to the absolute best of their (and your) abilities. That satisfaction of mastering a champion (or multiple champions) and using your knowledge to perform better and win games due to it is what motivates people to keep playing. For some champs, its easier to reach that point where you can achieve a goal easier than would be possible with another champion, but would there really be any satisfaction in that? Constantly going the easy route? Maybe, only because it'd help you win through less effort, and maybe simply "winning" is what satisfies you, but would that really make you a better player? Or just a better opportunist? Which would make you feel better about yourself?
Alright, that sounded kind of mean (sorry about that), but my point is, there kind of needs to be some champions that are harder to achieve certain goals with ("bad" champs) so that satisfaction is there for the players to earn, because without it, there'd be little reason to continue playing.
At least, thats how I see it. I play constantly to get better. The game is fun yes, but the satisfaction is what motivates me truly.
cough), thats a totally different discussion I think.