What I am most dismayed by is the fact that, in my opinion at least, Indy belongs to the early 20th century. The 20s, 30s, 40s. . . But no later. Crystal Skull pushed him into the 50s which means this film will probably push him into the 60s. The aesthetic will be all wrong.
But like you say, the whole thing can be saved by a good script, or at least it can wrap things up in a better way than Crystal Skull did.
After this I assume that Disney will essentially reboot the franchise. If they do, then I think they should lock Indy into that early time period I mentioned earlier and don't let him escape. Just have him go on a series of adventures.
Are you familiar at all with the British Poirot series? When Agatha Christie wrote her books, Poirot (the hero detective) moved through the decades with her. But when ITV adapted them, they reworked all the stories so that they all took place in the 30s. I'd like to see something similar for Indiana.