The biggest change is the tarmac on driver's left on the run down the hill to the Esses. That widens the road fairly significantly there where before it was just grass. Not sure if it means anything but the new patch of tarmac starts pretty much exactly where McNish left the road. Not that it would do anything to have helped a freak crash of that nature.
Everywhere else there was already tarmac at the side of the track in those places anyway.
I don't think it will allow them to cut the corners more. They take a bit of curb on entry to the Esses and barely any on the exit. That area beyond the curb on exit normally has green bollards over it anyway.
I couldn't tell you what's changed on the rest of the Bugatti Circuit. Don't care either.