I used to think (specifically around the time of the rumors of Shia taking over) that I couldn't see anyone else playing Indiana Jones. I will say, if they are going to continue/reboot, I could get on board with Chris Pratt in the role. I used to feel like they should just end it (probably with Last Crusade), but I think this whole new world of Disney's Star Wars has opened my mind a bit about these things.
When we first heard about Disney wanting to make all these movies (new trilogy, spinoffs, TV shows, etc.), I came to the realization (as silly as it is) that Star Wars was going to out live me. I don't mean to say that movies are so all important that you base your life around them or anything, but when the OT wrapped I think many were like "well, I got the whole story now", then that feeling continued with the prequels "well, I saw this through to the end". Now, there is basically no end in sight. I liked the prequels well enough, but the OT always stands superior to me and I realized that no matter how much Star Wars we get from here on out - or how much I like it - the OT will always be "my" Star Wars. Similar to how Harrison Ford will always be "my" Indy. I can let go of that enough to see a new person in the role, and for a new generation to have their own new adventures to follow (and I'll be there too). If there has to be a new actor, I'd be down with Chris Pratt in that role. He won't be Harrison Ford, but that doesn't mean they will be terrible either.