BWB would probably be the best/easiest way to increase efficiency over current designs by a significant enough margin to warrant a new plane. Adding in single pilot would further decrease operating costs.

A single pilot narrowbody could translate into two pilot wide body, as well as single pilot regional. That would also significantly increase the economics of a smaller aircraft especially these days.

Alternatively a new 737 type would just look a lot similar to an Airbus. Which is already out there and well designed.

I've read that the BWB has issues with evacuation times though,

Crossing my fingers for two pilots via FAA mandate though.