I think that they should chance the minis that are dropped via box or rng to tradeable item to allow people with the gold but not money to be able to purchase then, like the bank, and then add a second option to allow you to directly purchase the minis with gems, BUT they will be account bound so people cannot just but them for the gold.
This would allow Arenanet to be able to get people to use the trading post/rng mechanics for those who want to make money and allow those of us who just want the pets to purchase them without worrying about rng.