Tell me why in the world would they sell a disc dive-less version and not include a massive HDD?
As I said, it would include on board flash storage. And if that's not enough (which for non-casuals it most certainly isn't), then the option exists to buy a separate (probably proprietary) HDD addon at additional cost. In the end consumers are still paying a huge amount on the console, but by breaking it up and getting people to pay for things in installments MS would be able to fool people into thing the TCO (total cost of ownership) of the 420 is less than it really is.
And its no different that what Nintendo is doing with the HDD less Wii U, except Microsoft might actually offer more than the mere pittance of 8gb that Nintendo is offering. Let's say its 32gb or maybe 64gb of onboard flash. 2 years from now the price of that should be reasonable and therefore do able.
Let's not forget the original low end 360 SKU was HDD less, and required 256mb Memory cards, which were useless for anything except save information. Now their low end 360 offers 4gb onboard flash, which is still far from sufficient for any serious gamer, but again that's what the add on proprietary HDD is for.
And all the rumors say that Kinect 2.0 is integral to the design and will be included out of the box.
So if you are gonna have a dream scenarios, then they should both have Kinect in the box and either a BRD and/or HDD.
The thing about Kinect is its for casuals and it also requires a significant amount of living room space to set it up. Most hardcore gamers have zero interest in it. They like having their xboxes to play Halo or COD. Although, I suppose if and when Kinect compatible versions hit the market they may start caring about it. But right now Kinect seems to appeal mostly to kids and soccer moms, and not the hardcore crowd.