But that is exactly my problem, see you and I would like to make some actual money buying and selling things as a little added perk.
But you know there is some guy who never leaves Mom's basement that will try to make it his "job" and let's not even think about the 2000 Korean's who will have this as their job.
From there things just go screwy because "plat farmers" aren't doing anything wrong, heck what they are doing is sanctioned by Turbine.
I don't know if you were around much in the earier days but honestly I couldn't go ANYWHERE that wasn't instanced without spam in every channel trying to hawk Plat or Items for cash.
Turbine spent a lot of time and energy shutting those guys down to the point that it wasn't profitable for them to bother and it's more or less gone away. I hated those days, hated them with a passion.
This wouldn't crack the door open for them, it would remove the front wall entirely.
I understand where you are coming from but allowing this will have no positive impact at all. The only reason it's in Diablo III is because rather than try to fight it (which they did previous) they are willing to allow it to happen and just take their cut. And their player base is happier because they don't have to leave the game to go to eBay all the time.
I get it, I really really do, but I still think it's impact would be overwhelmingly negative.