Expanded decoration options at the other workshops would be nice. Barring the ability to decorate specific items, I'd actually like to see
Decorate Furniture broken into additional categories. Possibly I'd like to see the category of furniture broken up all over the game, but that's outside the scope of this thread.
As an example for decorating, I've got a decent-sized stockpile for exceptional-quality furniture, directly over my gem workshop. The only types of furniture allowed in it are the types that would most readily be used to add value to a room: doors, cabinets and chests, bags, statues, beds, that sort of thing. That in itself is a bit of, er, "gaming the system" to ensure that the dwarves decorate what I want them to decorate.
But then I realized I needed yet another kludge (burrows), because my carpenter's workshop is too close by. If the carpenter is building barrels and bins and the like, the gem setter is just as likely to grab a finished one from the neighboring workshop instead of encrusting the furniture in my stockpile. It was bad foresight to lay out my work area that way, but it would be nice if you could tell the dwarves to decorate more specific types of furniture.
At the very least, it is a bit odd that the game considers utilitarian items like mechanisms, pipes, millstones, buckets, and barrels to be in the same category as 'formal' furniture like beds, chests, statues, tables, and coffins. You can use some of the utility items to add to room value, but with the way things are now, it's as if the dwarf will grab the first thing not nailed down and speckle gems all over it.