Actually, it sounds like the perfect answer considering the character he played. There's nothing in the depths and minutiae of the Star Wars mythology that Harrison Ford would need to draw upon to aid in his performance of Han Solo.
Indiana Jones is sort of the opposite of Star Trek. The even ST movies are the better ones, while the odd Indy movies are better. (At least the rule applies up through the first 8 or 9 ST movies.)
Okay, so here's how they get around the issue of Harrison Ford being old and no one really wants to reboot:
Indiana Jones and the Fountain of Youth.
He drinks from it and de-ages into a younger actor. It doesn't really matter if the new actor looks like Harrison Ford since over the course of...
Oof..when you put it that way, if they keep the same relative timeline, and Raiders took place in 1936, that could put Indy 5 as late as 1976.
I really wish they hadn't skipped the 90s and made some Indiana Jones movies set in the 40s.