There's good reason for optimism, as Hanks has proven himself more than capable as both writer and actor. Sony just acquired the worldwide rights, which bodes well for distribution. And Hanks has based his script appropriately on C.S. Forster's "The Good Shepherd" -- which justifies the age of his character:
https://en.wikipedia.org/wiki/The_Good_Shepherd_(novel)
The one reason we might want to lower our expectations: the budget is about $30 million. These days, esp. for a war movie, that's not much. By contrast, "Captain Phillips" cost $55 million, and "Sully" cost $60 million.