I think things should actually be left exactly the way they are, as concerns itembuildr. One of the major points of itembuildr in the first place was to create a sort of speculative market for secondary sales for discontinued items. If the master ball turns out to be a hugely profitable item to sell on the secondary market, that will only fuel encourage more people to buy more and more of the next itembuildr item that will probably disappear in a month or so.

People buying way, way more of an item than they need from the Itembuildr store? That can be an significant flezz sink. Particularly if those people are so happy at the results of doing so, that they do it even more the next time. People buying master balls for 1,000,000   in kyoubai doesn’t add or remove any flezz from the economy (it just takes it from player A and gives it to player B), but somebody buying master balls from the Co-Op is sinking flezz. Somebody buying a lot of master balls is sinking a lot of flezz.

Why do we care if player A ends up with all of the flezz from players B, C, D, and E? It’s not like players B,C, D, and E don’t have a say in the matter, and it’s not like it’s hard for anybody playing this game to get tens of millions of flezz in addition to the best items in the game for every slot (except the headset). It’s not like there’s any value in flezz for endgame players other than “making the number go up”, so a speculative “invest in itembuildr items” game is a great gameplay vector for people interested in making the number go up.

Honestly, we need more things in the game that are awesome, expensive to buy from NPCs, and are only there for a limited time. We need more things in this game for endgame people to play with, and “playing around with virtual economies” is a lot of fun for some people.