If something like this was introduced to next iphone, everybody'd go crazy about it. Not only because of battery or HWKB...
Why do you think HW drivers are so difficult to open? The chip/module vendors should have nothing against that, since the use of the drivers implies the use of the respective HW blocks, which implies higher sales for the said HW blocks.
That IMHO looks more of a TODO sort of a thing - they are still deciding how to expose the 9+ running apps (a shelf, folder, more desktops, just show them, etc.).
Both BB10 phones as well as 808 have physical contacts to the cover if only to enable NFC so mechanically adding 5 more contacts to have full usb shouldn't be an issue.