They own the Pride library, right? So why aren't they using the awesomeness of the first fight to hype the rematch up? Are they afraid, that people will realize, how much more exciting Pride rules used to be?
The UFC doesn't always make sence. I remember when Liddell vs rampage II was scheduled and wondering why they didn't show the first one? They had the rights to the library at the time.
Blame the fighters, not the rule set/ring. There's plenty of legendary fights in PRIDE. (in before THP comes in asking why we're discussing fake wrestling)
They are probably worried newer fans will see their first fight and expect this one to come close to it and be let down.
They respect the fans too much. They know we don't think that they are the same fighters then what they were in pride. At this point in their careers their pride fight is irrelevant to the outcome.