My answer is that they should all make Superman movies, starting whenever they're ready, and put them out AS they're ready, and neither wait for each other nor complain about each other:
* MOS, with Routh AND THEN a third SR movie, with Routh, AND THEN a Routh-Bale Superman/Batman combo movie
* Smallville Superman, with Welling & the rest of the Smallville cast; as many Smallville Superman followup movies as they are willing to make
* JLA movie(s) with some OTHER guy as Clark/Supes. I've nobody particular in mind, but if they went with Tahmoh Penikett I'd be quite happy. No, his hair isn't dark, but that's minor. For JLA, I don't think they should use any main cast members from either Smallville or the SR series UNLESS they're in different roles in JLA
* as I've posted in other threads, I'd also be happy to have a movie with different versions of Superman (ie. the ones from the different movies/shows) interacting with each other to save Earth from some huge danger.
There. If it weren't for all of those marketing and studio and copyright-holding folks trying to keep the pie all to themselves instead of sharing, we'd be enjoying Superman movies at least once every year or two. Obviously those folks don't follow Superman's ideals all that closely - he sure wouldn't be biding his time trying to protect his bottom line instead of getting out there and getting something done! Shame on the studios. Major shame.