I’d certainly like to make a patterned glass block at some point as a more ornamental alternative to the plain glass block. We don’t currently have a system for changing textures based on adjacent blocks that would be required for this idea of framing ‘only the edges’, so that would require some engineer time on top of the usual texture authoring time to make a new block.
I do want to revisit glass at some point, but the solution is not going to be a simple fix and it’s just not a high priority right now.