I think trade chat and especially LFG is extremely plagued by advertising from either Boosts for gold/RMT or just money websites and while strangely this is something that is part of almost every game especially MMOs WoW seems to be the most stagnant in the issue. Everytime blizzard seems to implement a change it seems to just increase how the spammers get around them. The LFG tool is particularly spammed with tons and tons of people selling Mythic plus carries and Raid full clears and almost 99% of people absolutely hate this. PvP has also seen insane amounts of groups selling all kinds of carries and link different kinds of websites. While this may be something blizzard is not super inclined to crack down on it is seriously annoying to have it basically destroy finding certain groups or just general trade chatting
I think the easiest thing for blizzard to implement would be a captcha for LFG or maybe even Trade chat to push bots and spammers out of constantly bombarding everyone just trying to enjoy the game. Obviously this would be something that most people would be able to get around easy and it could even reward people just like 2 minutes of gametime for successfully completing it.
This is just an idea and a topic of conversation as I think personally not enough is being done about the sheer amount of bots and carries advertising in this game. Obviously running people for gold is bot illegal but I think the punishmebt for constantly adertising and spamming should be way higher.