Okay, after watching the actual youtube video (I really should've done that before commenting), I'd say they really need to rethink the actual way of doing it. Before this post I just glanced at the video preview frame and thought that was a conceptual abstract depiction of the idea, not how they literally thought it would work.

The kind of thing I would support is some standardized motherboard-to-component connector set, like in desktops and (to a lesser extent) laptops: If you have a desktop motherboard, you can virtually always stick almost anything into it because it has PCI slots for various expansion cards, the RAM chips have standardized interfaces so you can upgrade them (at least for a while), various disks are added through SATA or PATA plugs, etc. And while CPUs are a bit more limited in this regard, typically there are several different processes that can be plugged in to a given motherboard's CPU slot.

That's what I envisioned, small pieces of hardware, on the scale of microSD cards and microSIM cards and the like, plugging into dedicated slots in phone motherboards. And, if this PhoneBloks thing were to take off, that approach is what I hope they would take, though having looked at the video itself, I'm not optimistic.