"The whole idea of a 60-year-old (no matter how great a shape he is iin) fighting a 20- or 30-something opponent is rather ridiculous, but that's what suspension of disbelief is for."
I'm not a big Rocky fan, but am intriged by this one. I won't go see it, but I'll rent it. However, I did see an interview with him and the whole aging thing is part of the point, as is the old vs young. The premise with the computer program to see if and aging fighter would be able to beat the younger fighter is a commentary on all of these "marquis" matchups popular today. Does anyone remember George Foreman coming back a few years ago to fight some younger guy? All of this "sports entertainment." The computer program actually happened back when the original Rocky came out, it pitted Ali vs someone else (don't remember who). So, that part, oddly enough is more realistic than one would think. On the interview Sly indicated this is definitely the last one, but wanted to be able to wrap things up for the character and to end the series on a stronger movie/story than the way it had been left. He sounded much more intelligent than I thought he was.
Another Rambo, however, is a whole other story!!