Honestly think chat should not be punishable except in extreme cases.
There's a mute button. Use it.
Unless someone is shouting racial slurs, homophobic slurs, or culturally insensitive material, anything should go. This is a free country, and if things get too heated for you, there's a mute button.
This is how most games treat chat.
This is how chat should be treated in a country founded on free speech.
I am not suspended, I am not punished, I am not a victim of the IFS or any league of legends affiliated authority. I am just a person making an observation and voicing my opinion. We should not be banning players permanently for anything less than purposely offensive and socially unacceptable speech, as I mentioned above.
This is a competitive game. Chat will get heated. People will flame. People will argue. People will talk a bunch of shit. People's feelings will get hurt. Such is the nature of any competitive thing ever, anywhere, at any time.
The only reportable offenses should be leaving, intentionally feeding, griefing, and hate speech. Things like "Negative attitude" an "Verbal abuse" are easily rectifiable via the already-implemented mute button.
As it stands right now, people are afraid to use chat because of the inconsistency and (apparent) unfairness of the current system. Many players are opting not to use chat at all, myself included, because you just don't know what's going to offend someone anymore, and in this game - a player getting offended could quite possibly mean punishment for you. So why risk it? Just keep your hands off the keyboard. (except to control your character of course.)
That's not a healthy state for a system deemed by the designers as a critical part of the game. In a game where "communication is critical to success" players should not be scared to communicate for fear of punishment. Essentially, if you're not saying "Gee golly willikers, that play sure was swell, good job ol' buddy ol' pal!" with sugar and cherries and chocolate syrup on top, someone may get offended.
So lets do what most other games do, and limit punishable offenses to:
-Hate speech (racism, homophobia, culturally insensitive phrases, threats of violence) -Intentionally feeding -Griefing/harassing team mates with in-game actions -Cheating (third party software, boosting)
Anything else is unnecessary. If players don't like what's going on in chat, you've given them a mute button. Leave it up to them to use it or not.