TL;DRI want to enter a blueprint, run around in it and construct or deconstruct items at will.
What ?I'v used the Factorissimo mod, which has factory buildings that one can enter and work inside. I'm wondering if one couldn't make something like that for blueprints. You "enter" the blueprint and you get a new blank map with just the blueprint placed. The player inventory should get hidden and everything should be like in the sandbox with cheat mode on.
Ideally blueprinting should work and just place the entities. Deconstruction should be without delay (unlike sandbox, it's annoying there too).
On exit the blueprint would then contain the altered content, allowing one to quickly edit or even create a blueprint.
Why ?I frequently look at a blueprint and think: Wouldn't it be better if that electric pole would be placed one tile to the left? Or shouldn't that inserter be a fast inserter. Then I have to place the blueprint somewhere, run around in it and alter the item, make a new blueprint, change the symbols and name it. That is a lot of work for just moving or replacing one item. Worse with construction robots because then they start actually building the ghosts and I have to deconstruct them again.
At other times I want to try a new layout for some part of the factory. Maybe it works, maybe it doesn't work. But placing down all the entities just to see that one should have moved a belt one tile over is tedious. So I would like to start with a blank blueprint, enter it and then design there without the limitations of the real game. When everything is as I wish I leave the blueprint and print it somewhere.
There have been several times where I saved the game, quit, opened a sandbox, experimented there and finally made a blueprint and imported it in the real game. My suggestion would mean this would no longer be necessary.