Love the idea of a modular phone design to have components replaced as needed by the end user (open architecture) it revolutionized the PC industry (minus apple and at a point IBM). It would revolutionize the industry and could open the market up to a lot more players killing the duopoly is currently shaping up (Apple vs Samsung). It would also force Apple to rethink their own strategy as though they would try again to keep their system closed and again lose a very large market share. They have less fragmentation but the innovators will become imitators (MMJ). I agree also that this tech is only a few years out (the third party peripheral business will pour millions into this). The idea is scary good.
Want a better screen, no problem, $100 and plug it in (probably get less with more competition), faster processor (or more efficient)? no problem, $100 and plug it in. Camera, battery, wifi/radio, memory, case, speaker/mic.
Now if Apple is smart. they will ready their iOS with minimum specs and start migrating it to work with Android hardware or loose another market they started (they are notorious for it and when this initiative starts, I would dump all Apple stock). Microsoft I am sure has already started down this road (as an industry they started and has dominated [Start buying Microsoft stock now]).
The race is on! Main problem with current generation phones is the amount of bloat they contain...