I had an idea for a new Indy movie that would effectively put an end to old Indiana Jones and usher in a new hero/heroine. Since Disney are behind it, it probably means that they would be looking to do their own thing with it and maybe kickstart everything with a new Indiana Jones. It would play out over different timelines. You have old Indy going on his last adventure sometime in the 60s/70s, I don’t think I would literally kill him off, I’d pose it as the one mystery Indy never solved, kind of like a metaphor for death and passing on - with the world still so full of mystery. In present times, his descendent picks up where Indy left off, studying his old notes. The modern times would angle it that there is no more places left to be discovered, no more mysteries, everything has been charted etc. This young descendent of Indy is still obsessed with the big mystery of their grandfather’s last case. I think you could tell a really earnest story that deals with passing the torch on in a progressive way, within the themes of archaeology and ancestry, and the wonder of the ancients and the importance of coming to an understanding of the past.
Just don’t cast Chris Pratt as Indy’s successor. I heard it mentioned during the release of Jurassic World and whilst it would be funny to see old Indy ‘making up stuff as he goes along’ it like a pro, juxtaposed with his descendant bumbling along in a less savier style. Just no Chris Pratt.