That would've been all kinds of awewsome if they could've actually gotten Mifune to play the part of Nogura. I would've relished watching him and Shatner do the scene as it was written in the Roddenberry-penned novelization.
And if Mifune wasn't available, how about Mako? He and Robert Wise had worked together.
The meeting with Nogura would probably not help the pacing of the movie and wasn't essential for the general audience, but it sure would have been interesting to get a little peek inside Starfleet on that level. Also to see what Nogura's shoulder rank insignia looked like (assuming he wore them)!
Justin