As the title says, it would be really helpful if you could set up furniture settings while in blueprint mode - and perhaps even set a kind of default.
I am currently using the extended storage mod, and it is incredibly annoying to have to set the stockpile settings in between the actual building of the stockpile furniture and the first guy hauling stuff there - but there are many more and vanilla uses for this, too. You could set crafting bills when setting up the respective stations so you do not forget to do so later, for example.