There is another market-related problem, that should be optimised: a lot of people do not know whether the barterstands can accept the stuff they want to sell. Therefore, many of them make a very long trip for nothing, or have to wait for a long time for the barter owner to log in.
It would be nice if the barterstands would show how many empty slots the containers with red hands have. That way the traders could check the stands with their market-side alts and only after then decide to make the travel.