The OP specifically doesn't want attack move:
4# engi will not move to far in enemy territory!
Why they need path finding? They don´t have to move, just reclaim the current location.
It would be enought to scan every secound or so for some mass on the ground, every frame would be total overkill indeed.
In my opinion this would introduce a feature that will cap your skill ceiling, without you even knowing it. Similar to having custom strategic icons that are 2x the size of the regular icons. The latter is a choice because it is UI related. This would be either:
- Turned on by default, making new players unable to learn that you can easily rebuild structures and / or overflow a lot.
- Turned off by default and no new players would know this feature exists.
This game has already received a lot of automation in the past. This is one of those features where I draw the line. The alternative is to just attack move an engineer. That way you control what happens. And it is just two clicks. And it is already implemented .
If the OP or other people are that positive towards this feature - make a mod. Play with it. Then play ten more games with it. Then come back and tell us how it worked out while the engineers were reclaiming that T2 PD you wanted to rebuild.