Very mixed views on this. With only a 30fps increase, there is very little reason for anyone with the mark 1 to upgrade. Canon appears to lack innovation yet again. On the other hand, 4k is not readily available to consumers yet. Sure you can record whatever you'd like in 4k at weddings, but you have to downscale everything so you can put it on a dvd or bluray.. there is no universal disc yet that can hold up to 300gb, there are no discwriters available anytime soon if such a disc ever hits the stores that replaces bluray. The c100 is obviously aimed for sports / weddings / indy filmmakers or whatever so it is logical to have it only record 1920x1080 for the above reasons.Welcome to the forum. I also see no reason to record 4K today. TV sets in people's homes are not capable of displaying 4K. The Bluray disks do not have the ability to record 4K, without making dishonest compression that will steal the potential quality of 4K.
But canon does seem to scare the small film makers away.. thats a hefty price for only full HD, meanwhile you can get a a7s + external 4k recorder for only 4000 dollars.
Seems to me that there is a feeling like "I have a dick that is bigger than yours".