The title might be a little misleading. We LOVE raw footage but we only LIKE 4k. It could be because we've never worked with 4k or that I'm still amazed at the quality, with the right cameras, of 1080p (effectively 1k). We do love raw however. Raw is often described as the digital negative. This means that what you have is actually what was captured, no compression or limiting involved. This allows you to take video with poor exposure or color correction and specifically fix the problem areas. With compressed formats you can do a little of this but your working with interpretations of image instead of the original image.
Over at Philip Bloom's blog he writes about Why you Must have 4k and raw and why you absolutely DON'T need it. The gist is:
What's most fascinating to us at this point is how to shoot raw on our 5d mark ii. The Forum goers over at the Magic Lantern firmware site have some tips to make this happen. As soon as I get it set up I will get some tests posted asap.
Right now I'm more concerned about moving to raw than 4k so we will see what the future holds!