I don't know. Star Trek
worked because there was no movie of that name before without the sub-titles. I'd imagine that since Superman-The Movie is still a bit entrenched in everyone's minds that they'd have to add a sub-title to a new flick.
I just hope they don't waste time with an origin story. If you don't know that Supes came from Krypton, becomes Clark Kent etc. then you should go see the new Sandra Bullock movie instead.