They need to just start from scratch completely at a different site. They need to build a pure F1 / Moto GP track somewhere in the US, California, Atlanta, Miami area come to mind. Incorporate a long ( the longest & banked) straight in F1, another long back straigt, a couple of s turns ( perhaps a slight carousel reminiscent of Laguna and Belgium) a wide enought track for possibly multiple lines and overtaking, a figure 8 complex with the underneath tunnel structure ( like a combination of suzuka and monaco) and some slight undulation to make it intersting.
MOST IMPORTANTLY, keep Tilke far far away from the project.
My first choice would be in the Miami area. It would take full advantage of the South beach scene for fans and teams alike, and give the scenerary some character as well as phenominal weather.
Option A, street course around south beach, with indian river drive and ocean drive/collins drive as possible slower straights, or a new track on the main land , around theD olphins stadium, area