Riot works on its patches in two-week sprints, and sometimes these patches are pretty drastic (even within a season). This is a ridiculous rate of change, even if you want to keep your game from going stale. Starcraft had a long and illustrious competitive history, and it didn't undergo 2-week sprint patches. Neither did Counterstrike, nor DotA. League of Legends isn't the first big competitive game, even though Riot loves to pretend that it's blazing new trails and refuses to learn from history.
I don't know in what world ADC reworks take a higher priority than a client update. I don't know why on earth creating new champions is a higher priority than getting to work on those goddamn replays and sandbox mode. Seriously, the game doesn't need new champions when they already have this hard of a time balancing the ones that already exist. Riot's PR is god-awful, and their practices as a game developer are almost as bad. They're very, very competent as a business, thanks to the founding members having histories in business, but their game design is a bit lacking.
Their attitude towards addressing bugs is almost unacceptable. They almost refuse to publicly acknowledge that their game is buggy as hell. Bugs need to have a higher priority, and players should be told exactly what bugs are known and being worked on. You have no idea how many times I've seen a champion disabled due to a bug and then had to ask a friend what the bug was. Nice "transparency", Riot.
