That's my concern, too. They already made Indy into an old man in the last movie. I know the die-hard Ford fans like to point out that Ford is still in good shape, but regardless, the movie itself portrayed Indy as an older guy who simply didn't seem to enjoy adventuring as much as he once did. When Marion drove off the cliff, he told her "Don't ever do that again!" whereas in all the previous movies, HE would have been the one driving off the cliff. They tried to turn him into his father ("This is intolerable!", etc.) And now, as you said, we're 11 years after that, so who will Indy be this time? If they suddenly make him back into his younger, adventurous self again, it won't make sense. On the other hand, if they continue to make him even stodgier than he was in KOTCS, it will make sense from a character perspective, but who would actually want to watch it?