No power pass-thru/piggyback? Booo. I hope and expect that it's at least an in-line adapter like the Vita's, and not a wall wart (yes, I'm aware the Vita's is 5V).
No camera plug/USB pass-thru/piggyback? Booo. Hopefully they include a nice custom cable that blends nicely with the PS4 form factor. I like to use flat ribbon USB cables so I can route them down and underneath the PS4 to the back for a tidier look. Interesting that the USB plug on the back of the expansion box appears to be a micro USB2.0 plug, not a "double-wide" USB3.0.
(Edit: okay, so looks like no-USB-piggyback is still undetermined)
Someone could make a few bucks if they'd just develop a simple adapter set that changed the camera plug to a standard USB3.0 female port, with a corresponding adapter for the camera to make it a standard male, so you could add a hub in the back, or just use it standalone for other accessories.
Also, I really wish we could get more promo pics/gifs/vids in this side-by-side format:
I like being able to do the eye-crossing (un-crossing?) trick to get the 3d effect. It would also be awesome if they allow you to set the TV output from the breakout box to be in 3d for 3d-equipped HDTVs (though I've been disappointed with this gen's 3dTV support, so I won't hold my breath).