If they wiped the post-RotJ EU clean just so they could retell a major story from said EU, it would piss off pretty much everyone. It would straight up disappoint the people who never liked those books and were hoping for something truly original. Meanwhile, it would be like adding insult to injury for the fans that were still holding on to the now "old" continuity.

That alien might look like a Vong, but as Ridley Scott said in the Prometheus making-of, every damn creature design has been done by now.

Also, is that the Vong's chin or just a finger?

As for George's ST idea, well, it'll probably have something to do with whatever got discarded before he condensed the rest into RotJ.