Behavior and Honor System!
There are a few of us out there who try to keep as positive as we can be and understand everyone has bad games, but getting honored doesnt make people want to be nice to others, a nice way you could do this is that if someone honors you you can get extra IP maybe a little bit of RP or maybe even a whole new currency, like a token that can unlock a champion or skin for a day or two that you can use. If something like this was to be implemented I could see a big change in behavior of the community as a whole!