Every single design for the Douglass bridges messes up the issue. You can still have limited highway like bridge and make it pedestrian friendly.
Underground tunnels- continue the underpass right up to the beginning of the bridge in the left lanes while the right lanes would lead to street level; with that you could keep the park or use the land for something else while still allowing pedestrians a way to cross with little traffic.
Pretty much have a underpass that is decked over for 85% of the time from M Street to southeastern cross walks which would be moved an a entrance to the underpass would be there.
Entirely eliminating the underpass is likely being pushed by the property owner of the only building surviving from prior to the recent planning of the south Capitol Street corridor that of St. Vincent De Paul Roman Catholic Church.
RX- RETAIN the South Capitol Street underpass and extend it, widened with outside shoulders into a true cut and cover tunnel.
Consider extending it north, perhaps just past I Street.
Extend it south to the foot of the new South Capitol Street Bridge.
Consider a southbound underground off ramp to Potomac Avenue.
Design it to ultimately fit with a direct connection into the I-395 Center Leg that would accommodate a set of parallel deeper tunnelways extending beneath the Anacostia River to and from I-295.