Stephen, IMGoph, and Michael,
I considered the idea of a medial park, but worried that it would suffer from desolation due to its separation from the active sidewalks. Though certainly better than the status quo, I suspect fewer people would want to sit in what is essentially a grassy street median. That said, it would certainly be cheaper to build— and money is no small matter to ignore!

The advantage of the proposal above is that it enhances existing spaces (the sidewalks) whose heavy use warrants improvement.

decking over the block of north capitol street between T and rhode island avenue to create a park for eckington and bloomingdale is another place i’d like to see this done.