How about tying honor level to player's behavior?

Yes, we have honors for that. But what about reports? Obviously I mean the justified ones. If you say "gg ez" at the end of the game or call someone a noob or an idiot, that alone doesn't warrant a chat restriction, let alone ban. But it should count as a negative honor and slow down your honor level progress (or even downgrade it). It would also be good if the player received a notification about it. That would show them that this kind of behavior is not accepted and discourage them from being unsportsmanlike in the future.