I think davejames and I have been working with the original topic--if you're going to do a "Begins"-style movie, 1938 and/or with stripped-down powers are valid potential elements. But for another take close to what the OP suggests, I have previously advocated that if they were to find it necessary to do another origin movie, they should take their cue from the Golden Age comics and Byrne's reboot, and have him not even learn of his Kryptonian origins until after he becomes Superman. They could do an entire movie without one scene on Krypton, flashback or otherwise. Smallville could be flashed back to, in sticking with Clark's POV.
Was it the period aspect that made Sky Captain a flop, or was that the least of its problems? Seems like the Indy movies and Titanic
did just fine as period pieces. Was The Rocketeer
a flop? Just because one period piece flops doesn't mean another will.