While complexity =/= fun, it can be an important part of immersion, after the learning curve is overcome.
Because complexity DOES corelate to a higher learning curve, which can mean less fun.
This is not full casual game however, and I think slightly different rules apply. The more immersive it can manage to be the more fun it is. Thus the more detailed and less vague the vasrious skills and abilities can be, the more intuitive they can manage to be, the more fun the game will be.
Idealy I think the idea of a major, and minor skillsets would be best, with major’s having an impact on multiple minors, and the minors themselves having an efect on neighboring skills but would be very difficult to implement more so than it already is.
Detail benifits a game like cataclysm.
I can see a way to grey out ‘lesser’, or perhaps choose skill list order, other than skill level would to make the learning curve less difficult, as skills not moving around while you are trying to learn them, might make them easier to learn.
The crafting screen having a place for expected XP per outcome, per craft might help this as well.
Maybe a Training Mode or something, that better shows correlation(xp gain and such) between things that might be less obvious? But that seems like it might cause more confusion not less to new players.
The tutorial got revamped or something didn’t it? Probably the best way really. Controlled environments make learning easier.