Ya I agree, why 645?? Seems weird to me. It constantly amazes me that photo newbies with lots of bucks walk into my local camera store and pluck down a wheel barrow of green backs to buy the latest HB system. Every weekend I have been in there trying to figure out how to shave a few more bucks off the purchase of some 4x5 film a couple will come in and just ask for the best camera system they have..period. Major bucks later they walk out with the latest and greatest blad, telephoto, wideangle, metered head and several backs.
Mind you I live in a town known for it's abundance of disposible income, but geez. So it stands to reason that the well heeled bunch will look at this new blad and marvel at it's new lines and cute format so will have to have one. And besides it fits so well into the Gucci purse. I don't think serious photogs will consider this camera for an instant, unless they are out to impress someone.
If HB goes by way of BMW and concentrates more on pleasing the money rather than the serious driver, well there's always Rollei.