What if normal fabricators could only build structures that they have the blueprint for?

Just makes sense to me, since that is how combat fabricators and factories work. Makes you think more about how you use fabricators.

Combat fabs only do that because in the past the entire meta was based around using them to help build EVERYTHING in the game so quickly and so efficiently.

I'd really rather not do that with the other fabs, thats one of the fun things with TA-like games.

Yeah, I understand why combat fabs are like that. That problem still will exist to a smaller extent as long there are multiple types of fabricators. For example, groups of vehicle fabs are not useful unless you start with a vehicle factory. If you wanted to spam advance vehicles, then you would have to spam use a squad of vehicle fabs instead of just bot fabs + 1 vehicle fab.