No vendor buy back = trash game. Quit forcing players to use some arbitrary auction system that typically exists in the first place as a potential income source for the company; assuming they're greedy enough to come up with an even remotely workable RMT transfer system......
Lame just say you don't allow merchant buy back because items have much higher reuse factor in EQN and you don't want merchant diving to lower prices of items in auction house.
Then you know what just allow merchant buyback anyway because you have zero proof that it will actually harm the game. You're simply doing it because your computer nerd control freak nature based upon a unproven theory you have that doing so may be a good idea.
We can state as a fact that merchant buy back was a good thing in EQ we have zero proven evidence that any game was actually made better for not having it.