I think maybe it's not the role that's missing, but a vision on how to accomplish this under the constraints of modern software development. It seems to me that the core of it is for the lead to be able to break systems down into chunks where other devs basically just fill that in. Then in review the lead's job is relatively simple in terms of did they meet the requirements and is their style acceptable. Once devs are playing well in small systems, their responsibilities can be expanded. However, the agile process doesn't work well for this unless there's a place in the process for the lead to do this preparatory and review work, and a recognition that developers can only pick up tickets that match their demonstrated familiarity with the architecture and style laid out by the lead.

This is politically pretty difficult in most organizations.