There are a whole bunch of extra features tucked away inside HDMI. I know the Pi doesn't support Ethernet-over-HDMI, because it's missing the necessary PHY, but apparently it does support I2C-over-HDMI. I2C isn't very fast (tops out at 3.4Mbit, if you're lucky); is there anything else which could be used hidden inside somewhere?
One interesting thing about I2C, though, is that it would be cheap and easy to build a chassis with a whole bunch of these $5 modules wired together via I2C. It's almost certainly not cost effective in any way, but would be interesting, particularly if you could get useful work out of it...
Still, I for one would be more than willing to pay a few extra bucks for a stripped-down version of the Pi with wireless included.
Actually, all I'm looking for in this type of machine is Linux, Wi-Fi and GPIO, in a reasonably compact format. Maybe the Pi isn't a good fit, since it is more about "teaching computing" than "building your IoT stuff".
Like gp I wish some sort of network connectivity can be included to make it more complete as a standalone computer.
I understand they had to cut some features to reduce the prize. But networking is such a fundamental requirement for these types of systems, you'd think that it would be the last feature to be excluded.