I used to love this game more than any other I have ever played. In some ways, the game itself, is still a well designed work of art... however, needless complexity, change-for-the-sake-of-change type of updates and a hideously rancid community have taken the bloom off of the rose.
I still play, but probably only about 25% as much as I used to, and that is eroding moreso every day.
For me, I started to feel less passionately about League in Season 5. The Juggernaut update was a foreshadowing of the direction that the balance team wanted to take this game, but I thought maybe they would learn from these mistakes and make wiser decisions going forward. With a few exceptions, their continues updates and gameplay overhauls were further stunting my enjoyment of the game. The ADC update was an unmitigated disaster---so much so that Riot reverted one of the champions they changed (Kog'Maw) entirely! Then the assassin update came and I started to really lose interest after Kat and especially LeBlanc were marginalized substantially. I didn't even play LeBlanc much, and I was still outraged (this is how I felt about what they did to Morde also... I wasn't a Morde main, but I enjoyed a few Morde games now and then and he was forever ruined in my eyes). Don't bother arguing with me about Kat, either, I won't read it and I don't care what your opinion is... I hated the changes, period.
Every single champion has to have a gimmick, a three-hit passive, a do-this-to-do-that-to-do-this type of nonsense. Not every champion has to be overly complicated. This is a leisure time activity for the overwhelming majority of us, we don't need patch notes that read like a nuclear physics course, we don't need additional mechanics that add artificial power to the game (such as infernal drake).
I guess the biggest change or evolution in this game that has caused me to lose interest rapidly is damage creep. Damage has been, and continues to be, way too high across the board---with only a few exceptions... and mitigation options are far too few and far between. AD champions seem to have even more damage options then their AP counterparts and that should be addressed as well. I thought Runes Reforged would do that, but in many cases it just added damage to the game.
I'm not even angry about it, just kind of left feeling a bit sad about a game I once would rush home to play has become this sad shadow of it's former self.
The fact that Riot doesn't really listen to the playerbase or respond to posts such as those that I (and many others) have made through the years about the topics I mentioned above---or even in the rare cases they do respond they pretty much just tell you to 'deal with it'---has really soured me on the game further. Like a down-hearted husband who just can't bring himself to sign the divorce papers in the hopes that the wife will just try to turn it around... I sit here and still login, but it's really tough.