I find it interesting that comparisons are still made with the Potomac incident. Surely there's no real comparison because in that instance the aircraft stalled due to icing conditions and so came down largely out of control, whereas the Hudson landing was done with a glider with full control.
As with BA038, where I believe it has been shown in a simulator that it was possible to reach the runway, the benefit of hindsight and practice is what makes it possible. When you're up there and the engines quit with no warning, you only get one go. It doesn't have to be perfect, it just has to be good enough, and in this case it was.
Another example was American 191 at Chicago, where several crews crashed the sim having gone into it cold, but the crews that were told what had happened to the wing were able to recover and land.
Imagine knowing in advance everything that was going to happen - you could cut out most of the precautionary briefings and just do the one or two that were specific to your flight.