Perhaps automated is a bad word. I don't want them to build automatically, but I do want to see the mechanism by which we place them change. Using ALT and SHIFT is OK, but I do sometimes get the awkward placements.
Perhaps I just like the idea of quickly designating an area for "Minefield" status with a mouse and a quick click-drag, rather then build minefields in the same way as I do other ships. Minefields would not be placed where I didn't want them, and I don't think this kind of automation would be kinda pointless. I would still have to say where I wanted them built; the difference is instead of building a certain number until I have about the area I wanted filled up, I just say "I want this area to be a minefield", and let it work. I think this is not automation, but removing unnecessary micro.
EDIT: on second thought, I can see how the line between automation and removing micro can be blurry.