I say it ends with Ford. Unlike Superman, James Bond, and Batman, Indiana Jones does not exist without Harrison Ford. Indy was created as a movie character, first embodied by Ford. Those other characters existed in comic books and novels first. They, in a sense, transcend the actor who plays them. On the other hand, Indy is a screen creation, originally existing on film.
Unfortunately, as much as people compare Bond and Indy. I really don't think they're the same thing. And I really think we don't need to have 20+ Indy adventures in the future.
The series, as far as film is concerned, for anytime in the near future should just end with Ford. I've never liked the YIJC, and I think for the most part it's because I'm not watching Ford as Indy so I never really got into it that much. This isn't the only reason, but I'm not getting into that.
He just is the character of Indy, to me. Much of who Indy is is the mannerisms of Harrison Ford. Anybody else in that fedora is just that. Somebody wearing Indy's fedora.
Ford needs no replacement. Hell, he even shone in Crystal Skull. If Indy V does happen, he could be into seventies. Doesn't matter. Harrison in a wheelchair is better than a younger upgrade pissing on the legacy. And shoving Shia LaBeouf into Indy's spotlight is equally sacrilegious.
It goes without saying - but I will anyway - I'd be perfectly fine with the series being Ford-only. However, I could definitely see Eckhart playing Indy. Take the films back to the Raiders style of Indy being a little edgier.
Some of the McCoy novels would be great stories just as they are. Philosophers Stone and Secret Of The Sphinx would be perfect. They're dark and gritty stories the way Raiders is. They also take place just a few years before Raiders, so there wouldn't be an age issue.
"You want to talk to God? Let's go see him together, I've got nothing better to do. "