A couple ideas I've had regarding buildings:
bonus for size. This way we might be able to see mega factory / mega power plants. I'm think size should increase production speed but maybe.
Material requirement should be material or better. This way if I want to build a stone house I can.
Allow for two doors/ double doors. over-sized doors, windows, etc. I think this is difficult right now because there is no minimum block count, there is only minimum block of a specific type. If the minimum block count was more in line with the minimum volume this would just mean that if you want to have a very "airy" building you would need to make it larger/taller.