The first option that would be nice would be an Erase-All in the blueprint editor.
As I envision such a thing, you would be able to simply right-click on an item at the bottom of the blueprint where it lists the component totals, and have ALL instances of the item in the blueprint be greyed-out. We can already do this to individual components, this would simply streamline the process. Useful cases include: miscellaneous items like lights, and rail components that would otherwise force the blueprint to adhere to the 2x2 rail grid. Likewise, perhaps you ONLY want a rail or belt design, without all the peripherals, so this would let you quickly delete everything else. It would also have uses in large blueprints like this.
Go Ahead, TRY to Find All 22 Lights...
The second option that would be nice to be have, is a Replace-All in the blueprint editor.
Things like assemblers, containers, belt components, and inserters, already have the ability to be directly overwritten in-game, this would simply make it possible to do so in the blueprint. For simplicity, it could be restricted to stuff in the hotbar, since the current game already allows you to interact with the hotbar while the blueprint editor is open. As an example below, a totally epic train loader. Except, maybe you want a different belt tier, or maybe you want wooden boxes instead of steel, and maybe you want cheaper inserters... It would be nice to be able to simply drag the desired component (from your hotbar, perhaps?) and release it over the original, and replace all instances of that item within the blueprint.
Perfection. Except For Everything in it.
