I guess this could be viewed as yet another attempt to deal with the t1 spam.
Factories have the repeat button and rally points. This allows t1 spam to be fire and forget. Attempting to utilize t1 defenses to counter it puts you at a massive micro disadvantage.
I was thinking it would be cool to have an improved level of automation for buildings. As in the persistent build order persists even after completion. Hold down shift and see the squares under the buildings. If anything gets taken out, any construction unit assigned to that persistent order would rebuild whatever got taken out.