Orrrrrrrrr....we could just...let it go? Be happy with the memories we have of the originals and leave it at that?
Pshhhh. That's crazy talk!
BUT THERE'S MONEY TO BE MADE!!!
Huyang is right though.
You can't replace Ford really, but you also can't stay in the 30s/40s with Ford. The 50s of Crystal Skull was okay, but much later and you just don't have that serial vibe anymore.
It seems like the options are:
1. Keep Ford and let the franchise move into the 60s/70s
2. Hand off the mantle, but not the character specifically, to a successor-- Short Round, Mutt (ugh) or somebody else.
3. A combination of these two
4. A recast/reboot that takes it back to the 30s serial era with a new Indy
5. Recast Indy, set the movies in the 30s, but just pretend it's the same character despite the recasting so not a technical reboot
6. De-age Ford for one film, set in the serial era that sets up other adventurers working in the same way/era to force a shared universe of other characters we could follow in spin-offs
Honestly, NONE of these feels right. Indy isn't like Bond or Batman where recasting is part of its DNA... then again, Captain Kirk was recast and some people seem to think that worked out okay...