User blog comment:SpartanJ014/Forseeable problems on the horizon/@comment-7709681-20140120154351/@comment-5266525-20140120190939

I've seen that video before, and as much as I hate to say it, I'm not sure LoL is the best example of Perfect Imbalance (even though it cites it as one). It's not very common to have the metagame shift drastically between patches, and it's mostly Riot's balance changes that tend to shift power a lot. It even acknowledges at the end of the video that if player hatred often shifts onto a different target once their current one got nerfed, it's likely that they weren't incorrect and that champion really was somewhat out of line. Which pretty much is the case.

I don't think this is strictly Riot being bad at balancing, just more that they're trying to do the daunting task of making a perfectly imbalanced game while also making a game that staunchly avoids including any anti-patterns into their champion design.