Eurgh, tell me about it mate, these bots flood the marketplace with millions of each resource a month, it's absolutely killing the economy. The bots have always been bad, but the Grand Exchange absolutely made their numbers explode, so I blame that.
Can still remember when I restarted Runescape around the time the G.E was released, bloody hell it took a while to adjust, I didn't even know what it was for a few days, still sat in the banks trying to sell my goods.
The one thing the G.E did that really annoyed me was killed the social aspect of trading, back in the day you'd have businesses set up on forums that'd employ you, find you a buyer, set you a target (i.e 5,000 coal) and pay you for it and take a small cut for setting up the transaction. Now it's just 'whack it on G.E' which to me, has significantly improved the grind aspect, but now everybody is decked out in millions of gold worth of gear, you rarely see anyone who impresses you now. I remember back in the day seeing a Dragon med or a Dragon sq, and even the Dragon chain and thinking holy ****. These days though, if somebody is wearing any of them, regardless of their level, they get lol'd at and branded off as noobs. Heck, even when I used to wear full Dragon, with plate equipment, I'd get literal random abuse walking around, being followed by some fag in a phat, targeting me for being richer than most, but not richer than him. What is the point?
G.E also increased irl gold selling by a significant amount, too.
The fact the game had no form of an auction house set it apart hugely from the rest, lost a lot of appeal when the G.E hit the public.