I'm pretty surprised by how many people want RAW 4k video on a shoestring budget. Canon may be correct in pricing some people out of the market... I imagine a lot of cameras being returned once individuals realize that they can't possibly keep up with all that data.
I'd gladly sell my 5d3 and pay $8,000 for a 5d3 sized DSLR with true 1080p video detail similar to the C300. I'm not ready to turn my house into a data center to shoot the micro-budget movies I can shoot.
I wonder how many people who are clamoring for raw video have actually had to shoot and process it. It's possible, but it adds a lot of time to your workflow. Editing is extremely slow, vfx have to go later in the pipeline (after color), you have to worry about conforming and EDLs and all that good stuff, and color becomes a serious and involved step, not just a "throw magic bullet on it" type thing. The process sucks, which is why people hire out post houses. Do you get more quality from it? In theory... Is it worth it to you? How much time and money do you have... So yeah, I'd rather have a sharp 1080p dSLR than some crazy 4k raw contraption. Or even 1080p prores rather than 4k mjpeg.
That said, would you really pay an extra $5,000 for a little more sharpness? If you're shooting for broadcast or a camera for theatrical, you can probably afford a c300. The 5D III is fine for web. I mean, it really should be sharper and the lack of focus peaking, zebras, etc. is surprising, but it's not terrible.
These are two cameras for two different markets--digital cinema and videographer/dSLR op (ENG, weddings, no budget, anyone who's paid to take both stills in videos, etc.). The dSLR "revolution" was started by people in the latter camp, but all these new products (which look awesome, fwiw) are targeted toward the former. I wonder if the 5D III's shortcomings are a result of not wanting to confuse the two markets, or simply due to the fact that the 5D Mark III is a still camera first and Canon didn't think anyone would be too critical of the video if they fixed its most glaring flaw (aliasing) and slightly mitigated some other problems.