Fully possible to rebuild.
Just a couple bulldozers to clear the path and lay a new tarmac on it and job is done.
That would be too expensive. But they could easily recreate the spirit of the low downforce high speeds original circuit by simply overpassing turn 7 and going straight to the turn 10 exit. Problem solved. We'd get the high speeds back, the lap time and lap distance would be much closer to what is currently ideal (compared to the old circuit), no TV crew or grandstand would have to be set far away in the woods (which would remain untouched,by the way) and the calendar would gain one truly distinguished circuit which would add variety and allow less predictable results.
But F1 never goes for the simple and uncomplicated.