The game has had this problem for a long time, that a lot of games aren't fun because they feel like they are decided by who has the most of the current roster of "broken" champions.
There are the odd fun games where everyone is playing "fair" champions and you feel like you won or lost because of better teamplay and player skill, but they are sadly rare.
It's just that over time, the number of "broken" things in the game seems to go up instead of down. For every one that Riot fix, one or two new ones seem to crop up - or Riot just don't want to fix them at all, and new broken things crop up as part of reworks, roster updates or new champion releases.
It does feel like it's slowly getting worse instead of better, and right now it feels like it's the worst it's ever been. There's not just one or two outliers any more - there's so many outliers that even if you ban most of them, there's still a high chance that they will end up in your game because there's just so many of them.