A lower video encode bit rate means almost nothing for this title because so much of the image throughout the movie is black. And, every review I've read (by someone that actually has the Blu-ray in-hand) has given the image quality either 4.5 or 5 stars (out of 5).
I'm not worried.
If you want to see problems with a release, just watch 'All Is Lost' and watch for banding. UGH!!