I think a lot of it is just superfluous in it's current incarnation. Soap-making is pretty useless right now, but not intended to be forever.
Other "bad" professions (fish-dissection?)...well, we don't really have a good understanding of how important these jobs are, within dwarf society, do we?
Considering Carp, Fish dissectors might be every bit as important to dwarfs as priests, or even fire fighters. Not important to us, ofcourse, but a very respectable profession for them.
It would be nice to know if it really was, but that's part of the experience of the game: to decide for yourself what has meaning, and what doesn't.
I for one rather like the dabbling skill level. It's quirky, and not terribly important, but it clearly separates who's got serious knowledge, and who's just playing around. I think it might become a little more vital once teaching other dwarfs comes in.
Skill levels, overall, could use a little updating, but I'd rather see them expanded than contracted. Certain high levels of skill might, for instance, give boosts to the overall skill of any dwarfs working in the same shop as the High Master, because of that one's great knowledge and insight, while other "skill" levels (such as a peasant achieving Legendary from an artifact mood, for instance) could instead be used to denote respect, personal confidence, and political position within their respective trades, but have little reflection on that dwarf's mastery of every single aspect of their profession, or ability to teach/help others.