Shout cooldown
There is a lot of spammers. Instead of muting them (and possibly losing sales/trade messages from them), I believe a solution is a 30sec (or whatever) cooldown on shout chat. This should also help to stop Argentinians raging at each other 24/7 (I am also Argentinian and honestly it's annoying AF).
Either that or a trade channel with a different colour that u can mute would be helpfull aswell :)
I was going to add it as another solution, but given there is an idea already about an auction house marked as planned (which will partly fix this because no more trades in global chat), it wouldn't make sense.
Still, the spam and constant hostility should be somehow addressed.