Well ... it's a bit of a conundrum to me.
I've gone about it like so:
In my previous game, I started out creating larger Work Details, like Farmer, Artist or Builder - depending on skills and such. I found that the built-in Labors are quite handy, as it's easy to just toggle them on or off. Like, say, turning Hunting on and Off.
Generally Dwarves will do everything, but I think that if a certain Task is only enabled in Details that are currently on "Nobody Does this", nobody will. So it helps to keep a Work Detail to what it's all about.
Further, I remember Tarn posting about this, it seems to be intended that you rather assign a Dwarf to a certain Workshop if you want them to do something specific. However, if you assign a Metalcrafter but not Blacksmith (as per Work Detail) to a Forge, they'll only do the Metalcrafting Jobs, not the Blacksmithing. Which is OK I think, but a bit wonky given how you can tweak things.
I would like there to be some individual Job screen for each Dwarf - sortof like it used to be. Perhaps make it two checks - one being an individual Profile and one being the settings from the general stuff and you can easily see what is assigned to them Globally and whether or not you want them to do something a little bit different.
So if you turned off Hunting per the Labor Menu and you set a Dwarf to Hunt always ... they'll ignore the assignment per the Labor Menu. For better or Worse.
Eventually however, it'd be nice to also have customizable Icons for the individual Details. It was certainly the biggest Disappointment of the Steam Release.
Overall, in my current game I don't use Details so far. But I don't have a lot of dwarves either. It's however definitely a feature loss that sortof lessens the overall flair of the game. A bit. Since, things you could do you can't do anymore and there be some reason or intention but generally ... I hope it'll come back in.
It's not all bad - as the Dwarves will move around, Dabble a bit in everything - and how that plays out is a bit unclear.