Once you don't need a mirror to provide an OVF and PDAF, why compromise your lens designs (particularly wide angle) to accomodate it?
I'v often heard this but really where has mirrorless shown advantages in cost, performance or size so far? The NEX lenses really don't seem to offer any of them over a relgular crop sensor. Nothing I'v seen so far really hints to me that a mirrorless system that offered the same functionality(IQ, lens linup, controls etc) as current DSLR systems would be a signifcant advanatge.
My guess would be that the mirrorless market will end up running alongside DSLR's, smaller sensor bodies offering DSLR functionality but lesser IQ and AF as they do now and larger sensor ones focusing on pancake primes that offer a much smaller system.
I'd guess Canon's seeming lack of action could well be down to putting extra devolpment time into a system to get it right aswell. Nikon and Pentax's systems just seem like rushed jobs to me and I don't see either of them having much sucess, to do that I think Canon either needs to come up with a large sensor mirrorless with a good range of small primes at launch or a smaller sensor one thats much cheaper than Nikon's effort.