One possible way of making the strange moods system more interesting is introducing gods, demons and spirits as the cause of some of them. Gods could induce moods in dwarves who worship them and have a favourable set of attributes according to the god's sphere, demons would probably only care about attributes or just pick someone at random and spirits could use attributes/preferences. In addition, past achievements, such as skill levels and kills, should also affect this. Essentially we'd have 4 classes of strange moods which could interact with the current different moods. Having different entities preferring different kinds of moods, for instance a mood induced by a demon being more likely to be a fell mod, would also be pretty reasonable. You could also have different deities preferring different materials, such as a earthen god preferring to have artifacts made of rock and gems and a demon preferring to use bones.
The artifacts created from the moods would differ from each other. If one were to use the above system you'd get:
Dwarven artifacts: These have no magical properties, but are of exceptional quality. Same as todays artifacts.
Spirit artifacts: Slightly magical artifacts, with magical effects according to the spirits sphere. A sword whose edge never dulls, a bin which causes all items in it to become weightless, an axe which head could occasionally burst into flames et cetera.
Divine artifacts: Powerful magical artifacts, with magical effects according to the gods sphere. The same as spirit artifacts really, but more powerful.
Demonic artifacts: Powerful magical artifacts, but the magical properties comes at a great price. A sword which magically drains the life out of everyone around it, or induces a terrible rage which gives great combat bonuses but causes the wielder to go on a rampage killing everything around him/her until the sword has claimed three lives. A bin that magically creates food in abundance, but requires sacrificing an infant in a horrendous way.
Lastly, the deities could also punish unworthy wielders of the artifact. Worthiness would be determined by attributes/achievements/preferences.