Biggest problem with League right now: Clarity. Not the summoner spell.
My biggest frustrations in league right now have a lot to do with the amount of information being displayed.
Why am I not being matched based on my rank, but based on my MMR? What is my MMR? Why can't I get that information without having to go to a 3rd party site that can only estimate it?
Why can I not know how many reports I've gotten at the end of a game? Or my leaver rating? Or anything else punishment related?
How do I find out the numbers on champion abilities without going to some 3rd party sites?
None of these things are fully displayed in ways that we can understand. We don't know them, and thus can't adjust our play to them.