It was proposed to me in jest that an alternate exit be built on the east side of the HHP.
Its not a crazy idea. While doing so would cost more money than opening up the current exit to vehicles, its possible there could be federal money to pay for part of it and doing so would solve many issues with the current exit.
There would be no Amtrak involvement so this other exit would never have to rely on Amtrak approval and actually could happen quicker. Harlem would get the access it wants and also benefit by pedestrian traffic to Riverside Park.
The exit would not be so ridiculously long. Exit 12S is not very long. There is space to do this.