Haven't seen much discussion about this paid service Blizzard will offer, which I think is the only real issue with the TBC economy.
If a community pools up gold to reach gold cap (max gold + full inventory of valuable shit), sends it all to one dude, that dude uses the copy & transfer service (the stuff he has is worth WAY more than whatever the cost will be), and then sends it all to the next guy who does the same thing.
Theoretically it's possible for every single player who transfers to TBC to have gold cap this way, even if only one player on classic has reached that point currently.