I've been playing since before launch, and I've seen all sorts of "balance". When you read up and actually talk to the developers of this and many other asymmetric competitive games like this long enough, you begin to realize, if they don't say it themselves, that perfect balance is not possible, and ideal balance is illusory and virtually unobtainable.
The game was actually more balance with fewer characters and more radical moves in the beginning because of the uniqueness of every kit, most of them were powerful in such unique ways that left little room for comparison, they just brought totally different strategies to a team.
The way it is now, it's not balance, as I said, most characters are outclassed and unbalanced because they can't maintain a working balance for this many champions. Because you don't care about champions outside of your play set or haven't been around to see certain fiascoes doesn't mean that Riot is doing it's best. If they can't balance even one mode right, they shouldn't even bother balancing for multiple modes, they should just let players work around the tools available in each mode, as long as a character isn't wildly out of proportion, or a balance issue to SR, they can just let it be and let players us or ban it in other modes as necessary, unranked games have mirror match so players can match broke with broke, and ranked has bans so a handful of unmatched units can be omitted. As long as there are equivalent units to use for two teams, it doesn't matter if their all balanced, this is the exact same "balance" used in competitive play now, a certain portion of the champions are close enough in power to have a competitive match, you can't use just anything, some units have very few opportunities, some are universally outclassed.
And Riot is not some infallible or unapproachable masterpiece. it doesn't even matter if their talented enough to do a good job, because they intentionally ruin stuff with their poor priorities. The game has long been tailored to Esports which is a infinitesimal portion of the playing population. In a game where all their viewers are players, and where playing for most players falls withing average play... there is no reason for significant balance changes to be done for Esports. I've also seen them ruin dozens of champions and even entire roles and strategies not just for viewing priorities, but for inadequacy and unwillingness to invest in maintenance. But worst of all is when completely balance parts of the game are nerfed because they cause newb grief. Features totally balanced or even underpowered in regular and competitive play have been nerfed into orbit just because it's unwelcoming to unfamiliar players. Instead of making a complex campaign mode to prepare players for the features, functions and strategies of gameplay, they just drop content from the game indefinitely. If they ever get back to it, they often use cheap solutions because their too cautious to innovate in the game.
You can adore Riot all you want, some of us have higher standards, and some of us are far better informed...