Actually, it might be nice if the interface for constructions were redesigned a little.
The (d)esignation menu is fairly nice and simple - you can simply paint large areas for digging or channeling or stairwells, and if you paint a stairwell over a single tile in a place you've previously designated for digging, it will simply update "dig" to a "stair" command.
The (b)(C)onstruction menu, meanwhile (and why do we need to go through the (b) menu in the first place? Are these commands not used often enough to warrant their own seperate menu, especially since "C" isn't used for anything right now, anyway (at least, shift-c)?) requires you delete any designation beforehand, because you can't designate construction over any current construction, and must either make the construction fit the lay of the current constructions, or undesignate or deconstruct to make large designations make sense. You then have to find the material you want to build with the from the list of available materials (which can be QUITE long, and which the game never bothers to remember what you were selecting beforehand) for every single segment of designation.
It would be much better if you could have a construction menu where you could select a building material for all designations with one button, and it would keep that building material selected until you either ran out of that material, or selected a new one. It could also default to "whatever material is nearest" or "whatever non-economic material is nearest".
Then, constructions could be laid out using a menu not unlike the (d)esignation menu, where you could just lay out shapes, and it would automatically be filled with the selected kind of material.
As an additional nicety, I would like it if the material for a given planned construction were told to you when you (q)uery the planned-but-not-yet-built construction, and you were allowed to change the material for a construction when work had not yet started on it without un-designating the wall, and having to re-designate the wall all over again.
Finally, it would save time and stress to just be able to (q)uery a construction, and be able to see what place down the list of construction designations a given job was, and preferably give you a chance to bump something up in priority or sink it to the back of the list without having to undesignate and re-designate all over again just to wrestle with LIFO build order because you thought of something you wanted built, but want it to have lower priority than the things you were already building.