A good portion of the complaints regarding balance come not because Riot doesn't eventually correct the glaring issues, but because the company time and again takes comically long to do so. This season, we've had months of Ardent Censor specifically, and support itemization in general, dominating games. Enchanter supports rushing Ardent to win lane, junglers or tanks rushing Knight's Vow, etc.
Previous seasons we had Nidalee jungle dominating for who knows how long. Lethality abuse also lasted far too long. And the list goes on. Well, that's one of the complaints.
Personally, I'm of the opinion that the existence of a soloq meta is in itself a failure of balance. In competitive play, where slight advantages can win games, a meta is inevitable. But if for example in Bronze picking Janna is objectively better than Soraka/Sona/Lulu, the balance team has fucked up.