It is, ultimately, desirable that characters must expend money in pursuing their goals. The goal can be adventuring, mastering a craft, or becoming the #1 socialite, but being forced to get money for it, is one driving factor behind generating interaction between characters.
For myself, personally, I've only managed to ever master herbalism on any of my characters. Herbalism - and to lesser degree, alchemy - are fine crafts in that they produce consumables that have a constant demand for them. It'd say it's much tougher to find people who'd sell you potions than it is to find a buyer for potions. At higher levels, when money is rarely something that players really need more of, there's a tendency for herbalists to stop producing for general use, opting instead to only produce for their IC friends. This is a bit problematic IMO, but I don't really know an elegant solution to it.
With smithing, leatherworking and woodworking, I've never managed to get very far with them. Honestly, I don't feel there's enough in return for your time spent. Grinding them up can be done relatively fast if you wait until you're high level, amass enough money for it, and then just spam-create those boots all day. But I'd like to combine the grind with RP and have the character start their craft early on, and it does make it very slow.
Another problem with those crafts in my books is that there's simply not that much demand. A single active smith can basically produce for the whole server. Characters only ever need to buy an armor once, and bar losing them, may only need to buy a weapon and shield once. One solution I've thought of was adding means for crafters to imbue temporary bonuses on crafted items by spending crafting ingredients. For example, a master-tier swordsmith might temporarily (say, for ~1 real world hour) give +1 slashing to a sword by using a steel ignot. Or a skilled leatherworker might give a temporary 1 damage resistance against piercing & slashing by waxing a leather armor up. That way being good in a craft that produces singular, non-consumable goods would still mean that your craft continues to be useful even when you've already produced the goods in question to everyone.
Lastly, I think the design where crafters need to rely on each other to produce the final good didn't end up working as intented. Instead of leatherworkers and smiths working together, you just have one character master both crafts. This was already mentioned in this thread and there were some suggestions about making this cooperation easier, but it's hard to find a solution that both worked with NWN, didn't feel like a crutch, generated RP, and also felt plausible. I'm not really sure if I have any ideas about a proper solution to it. One might be that the ability bonus requirements are reorganized and emphasized so that it becomes very difficult for a single character to be able to master woodworking, leatherworking and smithing. But this might feel a bit too penalizing to those craftsmen who have trouble connecting with other players, be it due to timezone or perhaps due to the outsider status of their character.
