L'Enfant Plan is incomplete.
First of all he did not understand Montesquieu's 3 independent balanced powers of a Democracy: Legislative, Executive and Judiciary. The Capitol and the White House dialogue at both ends of the triangle, but the Supreme Court is not placed at the third angle, as it should be. The third angle is where Jefferson memorial is placed. Too late to revise that decision. But if we extend the 'other' triangle we find a potential site in Virginia shore that would open up a lot of other possibilities to respond to the Second mistake.
The Second mistake is the lack of an extended design to to the west shore of the Potomac. The Perspective of the Mall, beyond Lincoln Memorial, is unfinished. No design of the scenario of the Capital in the other side of Virginia. Arlington Cemetery Bridge is asking for a twin he was never granted. The intention was there when the Diamond was put in place. Lost afterwards when the west shore was returned to Virginia.
Is it time to revise both mistakes.