After taking a quick look at the specs - I have some questions (and recommendations) for the development team:

Do you HAVE TO use a FCBGA and 700 pins? That's quite a pain for troubleshooting and not to mention much more expensive for in the manufacturing process.

If it isn't too late - could you consider a QFN (or[T]QFP or something else non-BGA)?
There are probably way too many duplicate and unnecessary pins - probably with some optimization it will be possible to pick another packaging?
For example - there are 40 pins that provide IOVDD and IOVSS - do you really have to have 40 pins for that? Do they have to deal with that high currents?
Also - blinky stuff and LEDs don't have to have dedicated pins - the host microcontroller can easily deal with the blinking (if at all necessary).
Unless the temperature detector absolutely must have its own separate GNS - why not share IOVSS for example?
etc

And the other question - heat - what are the plans to deal with that?
Is the silicon going to be exposed (BFL-like) where users can attach a proper heatsink? Or is heat going to be dissipated through the PCB? If the second then bitfury-like packaging with a huge pad underneath the chip (and tons of vias on the pcb) will be better than a bunch of balls/pins.

And my apologies if some of that has already been answered.