Hands up anybody who'd recognise Pine's voice?
Anybody? Anybody? Bewler? Bewler? (Not you Mrs Pine)
That's kinda the point though. This is supposed to be something new. Nimoy is as much a part of the past as Kennedy and Armstrong.
People hear Pine deliver, "Space, the final frontier...." Fans will figure out who it is in a moment even if they've never heard Pine before. It would be the first realization that this IS something new.
Considering only Shatner, Nimoy, Stewart, and Bakula have delievered it before, in a way, it's a kind of torch being passed (that's cliche, but it makes the point). Hearing Pine's voice and seeing that Enterprise links him to it. This "Star Trek" is his.
It just seemed a forward-moving idea. The casual movie-goer may recognize Nimoy's voice, but I'm not sure that means anything. I doubt it puts more non-fans' seats in the theater.
I agree with Kegek
that the line is as much Shatner's as Kirk's. But using Shatner is, of course, problematic at best. And, I didn't mean this thread to be about Shatner, per se. He's had his threads.