I just spent the last couple of days trying to track down why a variable was being reset to zero whenever a second player joined the module when played in MP mode. It turned out to be a function I wrote that was buried inside an include file that helped keep track of module variables between modules in the same campaign. Thankfully, I tracked it down and fixed an issue with this and with the new PC/Companion AI that allows different players in the same MP game to control their own PCs separately from the leader. i.e. Players can control their own PCs independently of the leader with respect to stand ground and follow them. It may not be a major alteration, but it does make it feel like the players are more in control of their own group of PCs even though being part of the same party!
On a more positive note, I did manage to finish coding the "smelter" that allows a player (with a high enough skill) to smelt ore (five of a kind) into an ingot of the same material. And to make things easier for the player, they can add all the ore they have found in a single go and when used (closed) the smelter differentiates the different types automatically and even provides the remainder of ore. (It takes five ore to make one ingot.)
This is just another part of the crafting system where a player controls their components and is encouraged to make their own items. Don't forget that the economy of the system has been greatly revised, which means crafting/enchanting is a lot easier to pay for than it is at the moment. Of course, gold is harder to come by, and so will make gold a more attractive find as well. As a guide though, no single item can be sold for more than 10000 gp. If the value of the item is more than that, then it is considered a "unique" item crafted for the specific use of the player and no-one will (can afford) to buy it. (Don't worry, the smelter wll not appear on a carpet as it does in the screenshot!)