Well, it's a nice idea, but I don't know how useful that would be. I doubt that the selling player would get more electrum by selling rares to other players than by selling rares at the bazar. And even if he managed to get a "really good deal" I don't think that robbing newer player of their hard earned electrum for a few rares (which they would get anyway if they kept playing) is the way to go. We also already have a way of distributing a players rares in the community - the spins after each arena fight. The implementation of this new market wouldn't speed up player progress at all. It might even slow down newer players.