Give Riot a break! :(
Before you downvote, just know what when you complain about something on the boards: I WILL agree with you. I feel your pain. It IS annoying seeing Vayne and Kalista in every ranked game. It IS annoying that Riven is still OP. It is annoying that AFKs still exist and affect peoples' games. While these are very valid things to complain about, I just want you to think about these four things. :D
1. They're only human They're not gods with billions of dollars who will always make the right choices. They are humans that will make mistakes, but they are actively trying to fix them. Especially since Riot is made up of tons of people, they will often disagree with each other, making it harder to identify their mistakes and to fix those mistakes. So, don't expect them to fix these mistakes right away. Remember, time is the best medicine.
2. They've had success Though Riot has made mistakes, they have also had a lot of successful additions to the game. Such as the server move to Illinois which improved players' ping a lot. Such as the tank meta that replaced the annoying assassin meta. Such as the many creative champions that we only take for granted. There's so much more they've done that we should respect.
3. Believe it or not, League of Legends is important Well, by "important", I mean to the gaming industry. They have dominated the MOBA genre of games and are among the leading figures in e-sports. They are also among the most popular online games. Let me repeat that: They have dominated the MOBA genre of games and are among the leading figures in e-sports. They are also among the most popular online games. Please, just don't take this game for granted. :)
4. Though we complain, we still like League of Legends Even though we all complain about this game and its flaws, we still like it and we still play it. It's not as bad of a game as we think. (remember that "we" includes myself).
Though complaining is great and it shows what Riot needs to improve, I see things on the Boards that are just downright mean with people angrily agreeing with them ("people" includes myself), almost like some sort of rebellion. If you think about it, Riot is more likely to consider a problem if it's presented assertively than if it's presented aggressively. Just, please don't take these things for granted, and hopefully Riot will listen to the community more. :)