Diver Dennis:
This new Sony DSLR camera is supposed to be compatible with 16 million lenses.
There is likely 16 millions lenses that have been sold over the decades that will fit this camera. Is that a huge selling point given a LOT of these lenses are MF? IMO no, but it could make the camera appealing for those looking to get a bunch of glass on a shoe string!
Sony has 22 Alpha lenses, and that is likley enough for most shooters, and certainly worthy of consideration for those that have no investment in other glass.
Sony has also really put an effort into this camera as a complete system. Various flash configurations (like the macro twin), finders, voltage adapters, and remote triggers are available.
Build quality and speed are not equal to the D200, but it does offer a couple interesting features. Built in image stabilization, and a dust sensor are both features not found most DSLR's.
Is the camera worth a look. Absolutely. Personally I have no interest as I own Nikon glass. Will there be an UW housing for this camera? Hard to say.
It is always interesting to see how new DLSR's do in the marketplace. It's not an easy market to crack. Sony sure has put a lot into this from a complete system point of view.