Maybe the original narration didn't go well with Lucas' latest revision of history, so they just changed it. It may be worth going through looking for changes.

Anyway, if there was something really good about LD, it was the audio, so I'm sure if there is the new narration on the Blu-Ray, someone here is going to make a preservation using the superior Blu-Ray video and the original LD audio - if the BD video is considerably superior that is, I fully expect these special features to be SD only (just look at the running time) so with LFL's history of recycling old LD masters for the actual movies, it would be a wonder if they'd make a new transfer.