Personally, I want to see trash talking be punishable just on values alone. Heck, I'd say that we should give this a shot for a week, see what happens (I don't think Chad nor the Admins would appreciate that, though). But banning seems to severe; I'd like to see automatic mutes or periods where the games you play do not matter (wins or losses are not added to your stats overall).
Really, this entire argument is one big value/tolerance argument, and people are expect the staff to draw a line in the stand on some very grey area. Abuse, racism, insults are easy to pick out because they're ad hominem attacks that, if taken out of context, can still be seen as malicious. But trash talk must take the context of the game into account as well, since it doesn't make much sense if someone says, "Learn 2 Play" in real life. Plus, even if we made it filtered or bannable, people will find a way to bypass or just invent new terms altogether. All these factors are why the staff do not feel comfortable instating a punishment policy over using such terms.
One thing I will not flinch on: "gg" being a positive term. I don't know when the heck "gg" turned into an insult, but somehow it has during my tenure here. And to be honest, I don't think it's inherent to the term, I think it's a misuse of the term. Subjectivity determines whether a game was good or not, so whether the term GG is used positively or negatively depends purely on the user and the context. But I do not want to start a policy where, "he said GG when it was not a good game" becomes a legitimate report for a ban.