Stalls offer less and less products every month. I was inactive for half a year, and I'm really surprised, how much did range of goods being sold at stalls went down compared to what it was half a year ago, despite of some new stalls that were added. Stalls were originally a temporary solution to allow player trading, that never got fixed. Adding new stalls doesn't increase variety, since main issue remains - to get a stall you have to be well established player with some money on bank account and you have to be lucky to find empty one. This prevents most players from ever selling anything. It's like the game misses huge part of player interactions - trading, for vast majority of players its not a MMO but a singleplayer game with occasional raiding events. Though most players leave game before they actually reach level raiders get interested in them.
I suggest a small and hopefully fun idea. Boston gets new area - fair square. Once per week real time, or maybe once per season ingame time town Boston holds a fair. During this day players may open temporary stalls, that last 8 hours, for a small fee of few hundred coins. These fair stalls have only 6-10 slots and are specialized and require different skills to operate. For example farmer's shop would have no requirements but allows selling only agricultural products, tool shop allows selling only tools and requires 10000 hammer and nails, or arts and craft, high fee and 6 slots. Fish shop - only for fish and baits and with 7000 flora and fauna requirement, has small instalation fee and 7 slots. Restaurant allows selling cooked food, and needs 15000 sugar and spices, high fee and 8 slots. As you see different stalls have different proficiency requirement, different instalation fee and number of slots, this allows some fine tuning from develper's side. All numbers are just examples, proficiency requirement can be tied to some existing skills. As long as stall is active player is bound to it, unable to perform anything except chatting in local chat, after 8 hours money and items from stall return to player inventory.
What can be achieved with these changes in game.
1). it will boost player interactions, lot of players miss decent trading system. Actually crafting game without trading feels like donut without a hole. And this is NOT an auction.
2). Fair is fun, people come to trade and to get some amusement. Entertainment events happen on fair days.
3). Allows player specialisation, some players specialize in bees, some in fishing and they trade their respective products. Currently at least 90% of players do everything alone, from mining to fishing to crafting, basically they play singleplayer game. And like any singleplayer game, after at most two month you get sick of it. Trading and competing on market is a new game content for them and hopfully they'll feel like sticking with this game for longer time. More players - more opportunities for raiders and griefers, everybody wins. Also this will saturate market with basic stuff, and will open possibilities for advanced features and further specialization.
4). Coins become more valuable, especially for new players. This will increase demand for silver packs from game store.
5). Players who own existing stalls can make profit buying cheep on fair day and selling for higher price on any other day. Also some items can't be sold at fair stalls. For example inspirationals. Also temporary stalls would have low limit for what you can charge for a single item, for example 200 silver. Which means high-end stuff still can only be sold at usual stalls.
6). Specialized stalls allow some fine-tuning. For example you can make specialized stall for inspirationals, or clothing, or you can prohibit selling them this way alltogether.