They're pretty much screwed with the announcers either way. The old commentators either can't or wouldn't come back, and as much as people keep saying it, piecing together commentary from old broadcasts just isn't feasible, both in terms of effort involved and the likely lack of quality that the audio may or may not have.
So, that means Gorilla is a no go, and Vince... well, Vince would make sense and COULD do it, but my guess is that he wouldn't, simply to maintain the stigma of the Mr. McMahon character. To be fair, a large number of the people that are going to be playing this game have no idea that Vince used to be an announcer, they just know him as the evil boss. It'd be confusing, and unnecessary.
So, yeah, as much as I'd love to see commentary from the actual announcers of the 80s, I just don't think it's feasible. JR is a fine enough replacement, provided they have him record NEW commentary, as opposed to the same Smackdown vs. Raw ones they've used for years (On that note, I loved how in the last game JBL was just given the same damn script that others had been using for years. I mean, c'mon.), plus he's at least representative of the 90s, which at least half the roster will be from.