Add dynamic blueprint preview image.
A nice feature during blueprint submission would be validation of the blueprint string as well as then rendering a preview similar to the preview in the in-game blueprint. A list of components alongside a topdown view of each tile and entity would be the best. If not, simply a list of components in the singleblueprint screen would be the minimum for this feature.

Everything but the preview would be easy to add, because these things already exist in the SingleBlueprint component. Do you want to try it?
https://github.com/trakos/fbpviewer-js
The fbpviewer-js library should be able to dynamically render and image.
Factorio Blueprint Editor is newer and more full-featured.
https://github.com/Teoxoy/factorio-blueprint-editor