Yes, Canon does not natively shoot raw, but this is a ML forum and raw is what we are talking about, else we would be discussing this in a Canon forum.
So far for me raw has worked out well on the 650D, but other 650D users have had some hiccups. But as far as the 5D goes, professionals are relying heavily on their ML raw features on a daily basis and feature length films have been made using solely a 5D with ML RAW, so I can't agree with you that it's far from being guaranteed. ML RAW works, especially on the 5DM3.
Now Black Magic has it's own issues as far as RAW goes, and if you compare any BM and even most RED cameras to a 5DM3 using raw, the 5D delivers better images. I'm not going to go into detail of those comparison here for two reasons, one, this is a 650D thread, and two, you can find such comparisons elsewhere on the web.
I certainly agree with you that 4K is where the industry is heading, but right now the only viable viewing medium is a movie theater as there really are no mass produced 4K televisions available to speak of, and so if the theater is what you're aiming for, there are simply too many disadvantages of a 4K compressed image from a crop sensor to make sense right now for such a medium.
Let me say I've enjoyed our discussion on this matter and will be glad to read your response, but I won't reply any further to this specific topic any more, NOT anything to do with you, just thinking the moderators may not appreciate this lengthy of an off thread-topic discussion ;-)