TL;DR
Allow for blueprints/ghosts to be marked as "inactive", preventing automated construction.What ?
I propose a way to mark blueprints as inactive, or "do not build this yet", to prevent bots (and similar entities such as Nanobots) from attempting construction of placed ghosts.A selection tool could be used to toggle all ghosts in an area.
A modifier key could be used to stamp ghosts down in an inactive state.
A different hue (red, for example) could be used to visually distinguish inactive ghosts.
Dwarf Fortress calls this marker mode. While we're talking about DF, designation priorities are also a honky cool feature!
Why ?
Blueprints are a great tool for planning and layout, in addition to designating automated construction by robots.This is especially useful early game, before you have bots. You can lay out large chunks of your base and then manually construct things as you get materials for it.
But they are still useful mid-game. For example, for outpost construction. In a hostile world, starting by building the walls and other defensive structure is a good idea, but you first need to know how much space you need. Blueprints are perfect for this scenario!
However, as soon as construction bots hit the scene, blueprints lose their function as planning tool, as there's no way (short of removing roboports) to prevent bots from building a ghost in their range.
This is only exacerbated by mods such as Nanobots, or quickstart mods that start you with personal bots.