The Problem with the Report System is...

Feedback.

There is very little feedback when it comes to how often our reports actually lead to bans. As far as I know, you are only notified if your report in particular lead to the ban. I feel as if CSGO has a decent example of feedback (There are surely better examples but CSGO is a game I know gives some feedback.)

If someone you reported was banned a small notification appears at the homepage of the CSGO launcher that says something along the lines of "Someone you reported has been recently banned.. yadda yadda yadda.. thank you have a nice day." Even though this notification lacks the whos and whys, it still puts faith in the player that the system somewhat works,

I feel like Riot should attempt at feedback to players individually, that way players feel like their report matters and its not just garnishing as many reports as possible on someone.