10 bit 422 vs 8 bit 420
420 vs 422 only really matters in terms of color accuracy.  The significant part is 8 bit vs 10 bit.  The reason RAW files give so much recover-ability is that they are typically 12, or in the case of your 1D mark 4, 14 bit files.  Every extra bit doubles the total number of possible values that can be stored.  Some of this goes in to having more detail within the typical 8 bit range, but some of this also goes in to holding additional headroom above white and below black for a typical 8 bit image.

Even better than shooting 10 bit is to try shooting pure RAW video.  You may be able to actually try this with your 1D by using high speed cards and the third party firmware hack Magic Lantern.  I've used it on my 5D Mark iii and the results are outstanding.  It can record full 1080p resolution with each frame being a 14 bit raw file that has full use of RAW image correction tools.

Alternately, you can help increase recover-ability in 8 bit video by keeping your image away from the black and white points by decreasing contrast.  This will result in a more subdued image without color correction after the fact and will result in fewer total colors after expansion, but it will buy you room to deal with blown highlights and shadows since they will still fall within the 8 bit range of values.  This technique is often referred to as recording a "flat" image.