Making my first post in ages to put my measly hapenny in...
I am totally on board with casting a new actor for a new Indy, and Pratt seems to me to be, if not the very best choice (which I suppose would be 38 year old Harry brought back from yesteryear) then certainly a top candidate.
Let's face it, Indiana Jones is not Star Wars. It is a smaller universe with larger than life characters, driven by a mix of over the top set pieces and character building. Indy is a character whose history is many layered and rich with possibility and opportunity. Rather than taking the badass-but-aging Ford and putting him back in the saddle, after marrying his character off and giving him a dubious illegitimate son, why not take a younger, quite talented actor and release more films exploring Indy's very rich career?
In the end, Disney is a corporation very much invested in franchises, and casting a younger actor has more promise for the future of our beloved franchise than putting Ford's Indy in some psychedelic adventure in the Summer of Love.
So I'm all for it, team Mouse House all the way, raising my glass to the Second Star on the Right and all that other jazz.