Maybe I didn't understand you properly, but
wouldn't it be better to make a
list of acceptable licenses, instead of a single license?
Those are minor details. And I would dare guessing that for most of
the users it would make pretty much zero difference which free license
(FSF approved) the choose for their projects.
P.S.: by making source world-readable I was referring to unix
permissions, which would of course only have an effect for people with
toolserver accounts.