Edit blueprints

Having the ability to edit blueprints would be extremely helpful in many cases. For example, being able to edit out belts when belts aren't available yet would be helpful. It would also be cool to be able to move buildings or change the direction of flow within a blueprint.

while your example is, in my opinion, not a high level reason, I do agree that being able to edit BPs without having to place them on the map and then create a copy with your edits is an important QOL we should have - similarly to what Factorio offers in it's BP GUI.
moreover, this is what I had in mind:
since different research can impact which BPs we can use at a given time (like when a used item is not researched so the BP is locked) I think being able to edit a BP before bringing it to the map, or even in the BP GUI/book - as a new/changed version of the original - would make a great QOL. The original inspiration is ofc from Factorio, but I really feel it missing as an option when I want to use a BP (mine or other's) that is still locked due to missing researched items, like when I bring BPs from more advanced saves but a downgrade is not an issue (that is surprisingly dealt with, thank you)

It would be nice to be able to remove items in the Blueprint that I don't want. Now with the recent updates, Surfaces are forced into the Blueprints even when unwanted. I want to delete the Surfaces from my blueprint completely.