I like idea for muting players, there are some people are annoying but not reportable, but I would still rather not listen/read their chat.
Maybe they could add an ignore button. Make it so, that the player is ignored for, lets say, 3 days. That way they don't have to go through the trouble of implementing and ignore list where players could manually add or remove players.
I don't think it should be for 3 days only. To keep UI simple for devs, you could just have the button for muting change its text to "unmute" if that player is already muted.