I like the idea of blueprints, but only for small parts. I wont count the number of times I've thrown some pieces together in a particularly pleasing arrangement in one build then moved on to another only to get to a point where I'd say 'wait how did I do that again?' Thanks poor memory lol. It would also be good for large builds that have some repeating sections, just to remove some tedium. Blueprinting entire builds tho feels like a bad move. It could lead to laziness, sure I built an entire city in an afternoon but most of those buildings are just copies and some aren't even rotated.

To expand. Blueprinting parts would allow you to recreate entire builds, viking house corner a, corner b, c, hearth, flat roof part 1 2 etc. But in the middle of putting those prefabs together you might stop and think 'hey this would look really cool if i put a tower in this roof, oh how to get up it tho, i don't have a spiral staircase.' 10 mins later you make that staircase and add it to your library. Whereas blueprinting the entire build would be bad as then you'd just put it down and pay it no second thought. I know this as I've done both. I have used other peoples blueprints in games before, I've put them down then looked at them thought 'yeah looks good' and then moved on.