@Apollofunghi: If you approach bedroom construction as:
- Designate a bedroom to be dug out
- Wait for that to be finished, and then designate the construction of one bed and the construction of one door (which isn't needed, technically: dorfs have no concept of privacy).
- Wait for the bed and door to be constructed and then place it.
for every single dorf, yes.
You can, however, streamline the process a bit by:
- Order the digging out of a number of bedrooms (my standard structure means 20 per batch, but that's for low pop fortresses).
- Order the construction of as many beds and doors through the manager, or, as I do, have bedroom items constructed on repeat in the workshops (I want to eventually give everyone masterworks, but beds are placed as they're constructed and replaced later, with other furniture placed only when masterworks are available. The junk is disposed of via the garbage collector system [a.k.a. caravans]).
- Once in a while engage in bedroom construction/upgrade activities, i.e. place all the beds available in bedrooms (and, in your case, doors as well) designate bedrooms from all the beds installed since the last time. In my case I also designate masterworks furniture for installation (the crap bed is placed in one location and the final masterworks one in the center, allowing for a graceful replacement), removal of the old bed and designation of a new bedroom from the new bed when the masterworks bed has been installed. It's not necessary technically, but I typically allocate the new bedroom to the same dorf that just lost the bedroom.
While blueprint blocks would indeed be convenient (assuming you could specify/customize them to a "necessary" level of detail when it comes to item qualities, materials, rotation, and, possibly upgrade paths and priority orders), it's a lot of work to implement those and fix their bugs, and I don't think there' development time for that in the near-mid term.
Having the dorfs dig everywhere to make bedrooms would turn fortresses into the same kind of mess game generated fortresses are, and would interfere with essential infrastructure (no, there's no room for a well/cistern or the tunnels to carry water to it, because rooms block all avenues; no, you can't make a garbage/corpse disposal hole, because you don't have enough contiguous Z levels available, unless you want to make it an extra long haul away from everything else; Oops! Dorfs breached a cavern [or aquifer] with their room digging, etc.).