Great discussion going on at Psychochild and Hardcore Casual about what crafting is for. One point of view discussed there is that crafting is often done by socializers, who use crafting as an opportunity to stand around and chat. For that audience crafting shouldn't be too interactive, because if they have to click all the time, they can't chat simultaneously. For that kind of audience the current crafting systems might actually be suitable. But me, I don't really like the crafting system of WoW and other games using similar systems.
One thing I dislike is the current mechanism of resource gathering. It's fine that you have to travel around to find resources, but not so great that your success in resource gathering mainly depends on how many other people are online. Why should it make a difference whether I gather herbs or ore at 5 am or 5 pm? It only leads to players starting to hate the other players, who swooped in before them and "stole" their resources. I liked the resource gathering system of Star Wars Galaxies much more, where you had to prospect for high-quality resources that shifted position every week, and then harvest them, with the player coming first getting the best yield, but not a monopoly. In a game like WoW I'd much prefer if ore nodes and herbs would NOT always be in the same few locations, and if they would NOT deplete for all other players once the first players gathered there. What if resource nodes were redistributed every day, but would stay there all day long, and if you used a particular node it would be empty for you, but not for everyone else? Star Wars Galaxies also had one huge advantage in that copper ore wasn't always just copper ore, it had stats. Using resources with high stats lead to items with higher stats, while cheap resources with low stats were mainly used for practicing.
Regarding crafting itself, I'd rather an actual game to craft something. Best system I've seen up to now is smithing a blade in A Tale in the Desert: You start with a block of metal, a template which you should try to reach, and a set of hammers. You hit the block with the hammers, which changes its shape in a logical way. You can stop at any time, but the closer your metal block resembles the template shape, the better the quality of your blade. Other possibilities are systems like the one used in Puzzle Pirates: Every different craft is a different puzzle game, and the better you get with the puzzle game, the better quality of goods you can produce.
The basic principle for me is that crafting should be a game, an activity, with rewards that aren't much worse than the rewards from adventuring. Why should one hour of adventuring give you money and xp, while one hour of crafting only loses you money? People talk about adventuring having more risk, but that is an outdated concept dating back to Everquest, the last game where you could actually lose a lot by dying when adventuring. In WoW you can only lose time and repair money if you die, and that could easily have an equivalent in a crafting system. Craft badly and you lose time and money for materials, same thing as if you do a bad pull when killing monsters.
MMORPGs already have a variety of activities, most of them centered around combat: You can fight solo or in a group, against mobs or against other players. A crafting system which would be a game by itself would just add to the possible activities you can do in a virtual world. The more different and varied activities a MMORPG has, the more it feels like a world, and not just a linear game in which you rise to the top. The more there is to do, the longer it takes for people to get bored. Creating better crafting systems would be in the interest of the game developers.