After release of this game I have got only about 3-5 guild invites from gold sellers. Less than 10 mails. Seen the spam in zone chat only perhaps 2-3 times for a short period of time.
In my eyes, this is very little gold selling. I play on EU server, though.
I have yet to have problems with dungeon boss getting killed too fast, but I have seen many (not always) times the boss location being rather crowded. I do not know if these people are bots, but as said, they have yet to cause problems for me.