Personally, my money is on the deconstructionist perspective -- breaking down the classes into a master menu of point-weighted items so that characters can be built to a huge range of specialty classes, per level. The core classes may be included as example or for ease-of-play quick picks, but 4th edition will include even more plug-in elements.
I agree- I hope that classes in 4Ed will be more internally flexible, allowing players a choice of class features to customize their PCs without putting the PHB in the blender to have a whole bunch of classes on each PC.
Hopefully, with more flexibility, there will be fewer classes that overlap...
And I hope they either make Psionics core or drop it forever. I'm tired of classes my DMs won't let me use because they're "not Core." If they ARE Core, they'll have to at least give me a good reason not to use them.
That said, I'd be willing to bet that whatever the structure of the classes, there will be somewhere between not enough and too many classes in the PHB.