Totally would go for something like this. Don't know how implementable it would be but.
Me I build lots and lots and LOTS of overground forts. (holes in the ground kinda bore me. I've even built "aboveground" styled castles in the caverns before, because well, I felt like it) The most annoying thing to me is the hours of designating walls, internal supports (which aren't needed, but make me feel better). And eventually the removal of said constructions to build a new upper floor.
I've been able to get past some of the problems by saving. Setting up an external macro. Testing it out like 6 times (and usually failing at the designations)and then eventually getting a new floor to my main fort, or designating a couple more huts for my farmers to live/work out of.
I'd like the see a system added (kinda like quickfort/chromafort) but part of the main game, and with the ability to try to specify materials (I like my forts uniform color). Doesn't really need to do anything other than constructions, since most of the time, though buildings will be shaped the same, or floors will, they end up with different design goals.
Could also have the game store some basic building designs, that players commonly use. Like a basic 2 floor archery tower, or a small 9x9 building, with an opening for a door like many newbies will build over their first downstair. Perhaps it could take the form of a "architect" noble who when they get their time in their office, they will take the time to make the mass designations for the different floors for you.
In the case that materials you demanded for a building aren't available, he'll pause the game and alert you. Perhaps also it would allow you to designate structures of a certain material, even if you don't currently have that material. Then as mats become available, he'll order workers to press on, similar to the current Manager noble. Then in the meantime, he can run around and build the bridges and furnaces like the current architect does.
Stored building designs BTW, are stored separately from the world in your folders, so one could send their preferred designs to a friend. Perhaps make it so the arena can pull a building design in and use it as the base of the arena world. This could be useful when siege weapons are used by enemies, to test base defense strategies. Last but not least, perhaps make it so you can designate an area of building already done, and copy and store preexisting structures.
This is a good idea. I support.