As I understand "mastering", the 2003 release was a SACD mastering of the 2003 mix whereas the 2014 release was a DTS-HD Master Audio mastering of the 2003 mix.
Aside from that, my personal concern is that the 2014 surround release sounds harsh to my ears. I have ordered the 2003 sacd and it is currently in the mail. Your interpretation of the facts dictates that they should sound identical. So for me the proof of our debate will be whether the sacd version and the blu-ray version sound, fidelity-wise, the same or different. As soon as I receive the sacd I will let you know my opinion of that.