This was going to get added on to this idea but I think it may deserve its own.
A lot of companies use curtain walls for their windows, but you have to create a custom tag to make it look like a window, but on a mixed use of regular window families that do work and curtain walls they are on separate schedules.
Allow for curtain wall types to be assigned as windows. Even better, allow the ability of these types to be design locked and be applied to multiple locations. Yes, this is what Groups do, but groups tend to cause issues along the way, and you can. Perhaps a curtain wall family template? It can use all the profile/mullion types in the project, but they can only be modified or created as a separate family but all the tools of the curtain wall within the project. (Curtain Grid, Mullion, Add/remove segments, etc)