something i typed at the shia forum:
luckily, indiana jones can't really get rid of harrison the way star wars did. harrison's been the one telling george lucas when he's nuts for decades.
"you can type this s---, george, but you can't say it." --harrison ford on the star wars set
he even made a comment during the idea brainstorming that he wouldn't be in a spielberg movie like that (some of the early script treatments that were craptacular).
also--big difference... lucas has yet to write or direct an indiana jones film. empire strikes back (by far the best star wars) is practically disowned by lucas because he had the least amount of involvement in it.
spielberg and ford have fairly good sense in comparison with george. george has great ideas, but other people need to help him form them. that's how he's always worked.
and no. NO indiana jones without harrison ford as the star. just no. no. no. no. i like shia. but he's to the franchise what all the other friends of indy were. indy remains the banner name. shia can do lots of heroics in the series, but indy is still the big boss man as far as what the film is about and always should be. and a spin-off... such a bad idea. young indy, imo, actually worked for me on some levels. but it was more a history lesson (i'm a nerd) with some fun heroics and great humor thrown in (young indy getting rid of dinner guests by telling them how mummies are made was great--the only one left at the dinner table was henry, sr.).
a mutt spin-off has a few problems. with the immediate timeline, you can toss in a sequel or two into the late '50s and perhaps as late as '62. after about '63 the way of the world can't function in an indiana jones film. it's the end of that innocence and even capability to be so far outside the rules that indy is. the 1800s imperialism through the 1930s was a very anything goes time period for adventures and maverick archaeology. you could still get outside world rules and laws. science wasn't so advanced that you were being tracked by high tech gadgets and you were controlled the world over. villains didn't have outrageous technology for an archaic figure like indiana jones (who, let's face it, is dressed like a lion tamer). the '50s were really the last decade there was still a bit of that innocence about the world. you take mutt and how far can you go? there's about a 5 year span between 1957 and 1962 where the '50s culture still existed. after that, it's just too modern for an adventure film. the '50s were the last decade where cowboys were still at the height of pop-culture. you had the space race encroaching, but cowboys still existed. you still had zorro, the lone ranger and davy crockett. indy still survives in this climate. but once zorro, the lone ranger and davy crockett (the raccoon cap fad!) are gone... indy just can't breathe as a genre.
shia is only 21. that's also an issue. harrison was 37 years old in raiders of the lost ark. a mutt spin-off would be closer to the young indy franchise in an era where adventure already was dying, rather than at its peak during the young indy years. mutt's world is more at home in american graffiti than maverick archaeology. mutt would be entering the world of regulated science (the kind where you excavate with a fine brush) if he takes after his dad.