Dear god, someone actually liked Never say Never!?!?!
Seriously though, I loved View to a Kill...and that had a VISIBLY aging Roger Moore at the helm. The thing is, though, that by that point Bond movies weren't the bang-up beat-em-up action films they used to be, they were relying more and more on "prop stunt" sequences than actual physical activity by the star. Lots of huge battles where Moore basically just ran through them, often with the damsel in distress in tow. So it was ok that Bond was looking like a 60 year old, and not a 30 year old.
Now, this is fine, as I am a firm believer that stunts ruin a movie (action sequences take precidence over an actual plot, and last time i checked Bond wasn't supposed to be a Ninja nor an olympic quality acrobat, which some of his sequences can turn into).
HOwever in an Indiana Jones film I expect some things. Nazi's, for one
No way is 65 year old Ford fighting Nazis...well, maybe modern Nazis in the 50's or something
Spielberg and Lucas and Ford will most likely try to do another "Amazing Stories" kind of film...so we know it wont be modern, but it probably wont be feasable to set it in the 40's either.....so its uncharted ground no matter how you look at it.
I guess I had just better prepare myself for a film where the age of the stars is the focus of the movie, lots of self-depreciating humor and such. It could work, because Ford does comedy really well....but at the same time I keep thinking of those last few Star Trek films, which were atrocious.....