Pulled up from the comments
The comments ... proposing alternative intersection types at connectors such as 14th Street Bridge, 4 Mile Run and the linkup to the Pentagon are being actively pursued by GWMP. Preliminary studies and designs have been done, most notably at 4 mile run, and hopefully some of these projects will be built soon. Of course, many of these improvements are contingent upon financial resources, but the concerns and suggestions of the cycling community do not fall on deaf ears. The first steps in studying and building these improvements have already been taken, and there are several advocates within GWMP who are pushing hard to ensure that the MVT will be a priority project for the Parkway.
NPS Transportation Scholar for GWMP + National Capital Region