I do like the market, but I wish there was more action. Having it be player-only seems a little odd, mainly because there aren’t enough players to approach anything like “real” prices. Perhaps if there were some NPC trades going on semi-randomly that could set some basic prices for starting items. It could also give an outlet for some items other players might not need repeatedly (one pair of binoculars is probably enough). It would be nice if the existing trader NPCs came more in line with the market in terms of prices. Since they were made when gold ingots were the only currency, the value doesn’t line up very well. I’d like to see traders that didn’t price gouge so much. It might be helpful to come up with an algorithmic way to determine “real value” of items. Something that takes into account rarity, effort to collect items, usefulness to players, and effort to craft. Then the NPC traders could pick a random mark-up (e.g., 15% to 100%) and charge that many coins.
Side note: I’ve still never seen natural mithril, despite having dug down to the nether by hand (well, technically pickle).