it is an interesting concept, the swappable cpu is a must, as stated not hot swappable but doable. What would stop me from jumping onboard with this idea is the screen being set, with advancments it seems a few years back 720p was the bees knees, now 1080p is standard and we are moving beyond it in the high end. I understand that in theory one could buy a new platform and plug iun thier components keeping a backup screen/dock, but i would want some sort of guaruntee that the standard would last for several years so when i wanted to upgrade a screen my other components would still plug into it, otherwise unless it is reallycheap i can't see makign the investment.
my other concern is with the S5 and Sony phones other manifacturers are bound to follow suit with water proofing and water resistance, I can't see how one would effectivly make somethign like this waterprof outside of a aftermarket case, in some parts of the US and the world that is no big deal, in Florida where i live it rains most dayys and often out of nowhere. so any nonwaterproof or phone that I can't buy a reliable waterproof case for is out. (though I have a Nexus 5 now and am just tired of carrying aroudn emergency waterproofing devices (ziplock bags) in my pockets all the time