But he has no clear data black and white on the current system, no proof whether it will be beneficial or will it be found deficient compared to the actual testers that are playing the game. Feedback as we call when we are designing a system. Yet hes talking off a chicken's backside with nothing to show.
One thing I can tell you for sure is that the market in any game (f2p MMO) will be either lead by either cash shoppers or bots. In this specific case of the OP it's horrendously skewed to cash shoppers favor compared to a f2p player (and even bots lol). Even though the npc gives a price ceiling for the brown box in the market it's laughably far off (currently at least). The only somewhat fix I can think of (including u70 stones while we're at it) would be to have occasional events for these items. i.e. increase drop rate for upgrade stones during the weekend, 2 hour brown box drop event that any mob can drop, or being able to dismantle dogis for dogi balls with a chance to get rare dogi balls. Regardless of how you'd do it so long as the cash shop performs as purely vanity/accelerator as opposed to a dictator I think it wouldn't be too hard to find a balance.