Good read. I looked at a few of these boards, but they just seem lacking in some way or are not as thin as they potentially could be.
Couldn't they make a fully featured enthusiast Mini ITX or micro ATX board that could match the performance of a regular height board, with these changes:
1) Half-height on the I/O connectors
2) Two slots for 260-Pin DDR4 SO-DIMM
3) a 90 Degree x16 PCI-e slot
4) At least one M.2 slot
5) 90 Degree connectors for the 24-pin ATX, SATA, and the 20-Pin USB 3.0
That would be killer... because at that point the tallest component would be the I/O slot.
Now I know that most enthusiast boards need heatsinks on the VRM.
So if there is only half height to work with, they can add a heatspreader like this:
across the motherboard surface to contact the VRM and other hot chips?? 
I know that they make DDR4 3000 speed laptop ram, so it's possible I hope
