I haven't quit but I have been playing A LOT less. I was gold in seasons 4 and 5 and had a couple ranked teams floating around in silver. I played several games almost every day. But now I play 1 game every 3 days or so. Always with friends and always a normal game. No more ranked for me until solo queue is here. I've also stopped buying RP in season 6.
In the meantime, I've been in the Overwatch beta so I've been enjoying that. No solo queue in that game either but it's a closed beta so there probably isn't a population to support it yet. After the beta goes down next week, I've got a few games in my Steam catalog to go through, Far Cry 4 primarily.
Dynamic queue has really soured this game for me. I actually was for it when it was introduced but its flaws have become very apparent and I don't like Riot's attitude towards criticism of it.
But hey, they buffed my favorite viking.
So I got that going for me. Which is nice.