This is always one of those topics that's hard to approach. You either come in with a clear bias, or you're in the neutral ground, can see both sides of the argument and thus provide no real support for either side and watch as both sides make good arguments, good enough that neither side can really budge.
Competitive vs. Casual balancing is always very difficult to approach, whether in RTS games, FPS games, PvP-based MMOs, MOBAs, etc. If a game leans toward balancing toward casual play, the competitive market is going to die off because the game won't have enough depth for that kind of devoted play, and if it's balanced toward competitive play then the casual aspect of the game is hurt because there's going to be all sorts of arbitrary limitations and rules set that are in place solely for the high-end organized and competitive brackets. One could say that the game should cater to the casuals who foot most of the bill for the game, but on the other hand you can't ignore the people who put by far the most hours and dedication into the game and knows its inner workings better than anyone else.
I used to think the LCS, and other competitive elements of the game, were ruining it, but now as I sit back and look at it from an outsider's perspective (since I don't play LoL anymore), it gives you a different perspective on what it does to the game as a whole. From the perspective I hold from playing other games since League, it feels like League pushes out balance patches too often, and they're a strange mish-mash of competitive and casual balancing (which is fine, nothing wrong with it just because it seems strange). As a result of the comparably fast balance changes the balance decisions are often not well thought-out for the long-term, and the players also don't get to have a truly firm grasp of the balance of the game in a given state, which ends up in this see-sawing motion of champion balance where a champion goes up... then comes down... then up, down, up, down. Pair that with the fact that sometimes those balance changes are fairly drastic, in the middle of the season no less, and you end up with a game with very chaotic balance and nobody knows if it's because of a focus on casual or competitive balancing, except it can't be just one side's "fault" because the balance notes often include changes to placate both sides of the spectrum.
I used to think the LCS was ruining the game, but if the game's being ruined then, in truth, it would be both sides doing it in, not just one side. Both sides have input in the balance notes. You can't just demand that your input be just as valid but if anything goes wrong then it's the other side's fault.