I don't watch the minor trolls, and in fact the ones I tried to make sure were reported weren't bad enough to make the list (though it was close with the braum since he started his harassment in the select menu and never stopped), I only re-looked at them after they sent the chat logs for those games. Even the one who was calling my top laner a "ni gger" several times didn't make the list because it wasn't quite trollish enough because my top laner wasn't doing great and when I stood up for him and told the mid-laner to STFU he's doing fine and we can still win this if you stop being a jerk" he only called him a "ni gger" once after that.
These aren't 30+ maybe trolls, these are 30+ troll from start to finish trying to make the game horrible for everyone trolls. Not a single one has ever been punished, but I got punished for trying to make sure trolls were reported. I thought maybe people just aren't reporting them enough in one game to make the lists. Now I have no other things to try to help riot find trolls. Even I'm out of ideas. Riot just doesn't care and I can't do it for them.
My position here is based on never seeing any trolls ever get banned despite putting the worst ones I've met on a watch list; RL death threats, trying to get their own teammates to kill themselves in RL (both of which I sent in support tickets and all 4 are still playing without ever having a lapse in game play), people who start the game spamming "fa ggot", "Ni gger", "noob" and more all through out the game for no reason, feeder trolls, and all around the worst trolls who do it on purpose but Not a single one has ever been so much as temp banned. Now I often say "never punished" because you'd think 50 messages of "fa ggot" would give more than a chat restriction, telling someone "I'm going to find you, come to your house and fu cking murder you fa ggot" would be worth more than a chat restriction.
Again and TL;DR, None of these are mediocre. They are the ones that without a doubt troll on purpose for the sake of making the game horrible for others to play. Only the ones I am 100% sure are trolls and 100% sure are the worst make this list and not a single one has ever been punished. Please keep that in mind when I talk about player behavior.