Market Place

What about a Market Place?
Many games have it. A place where you sell anything you want at your own chosen prices, and other players buy it or not. So prices could be high or low at owners discretion...
Here you could sell/buy anything from gems to skills.
The products would stay for sale for a period of time, like 24h.
Would still keep the option of selling it back at a standard price, like happens now!

Market places and auction houses encourage botting. Makes more work for Haypi.

Although it would be a nice feature to have, creating a system where players can trade items and monsters will create a lot of problems.
Firstly, accounts will be more susceptible to hacking because of this.
Hackers are not prevalent in games where there is no trading system because there is no point in that as hacking someone else's account would only let you play with his account. You still have to properly play the game to progress - so why do it on someone else's account, which is most likely already known to other players and, thus, creating a weird atmosphere when logging in.
With these threats of hacking, the company would have to invest in an expensive anti-hacking shield and I don't think it's wise to spend too much on that if the game has just been created.
There will be a lot of support needed - with players facing a lot of problems and seeming to face problems, such as being deemed to have been scammed, etc.
This is one for the future but it is too problematic and tedious for now.