I agree they should plan for a 10 year run, so, it would be wise to target 35 or younger for Bruce/Batman, but, I don't think they should automatically rule out a little older if someone perfect comes along, there's alot of 50 year olds in Hollywood that are still pretty young. Ben Browder will be 50 in December, and though obviously you wouldn't want to plan on him for another 10 years, he still is young enough to play a Batman character today (Not that he's necessarily right for the part, just an example of someone still young enough at 50 to be able to do the role)
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?