You seem to be confused. DXO rates the color depth of the 6D and 1DX at 23.8 bits. The rate the 5DIII higher at 24 bits. That is backwards from your observation.
From DXO's web-site, RE: color depth.
The higher the color sensitivity, the more color nuances that can be distinguished. As with dynamic range, color sensitivity is greatest when ISO speed is minimal, and falls rapidly with rising ISO settings. DxO Labs has focused on measuring only maximum color sensitivity.
A color sensitivity of 22bits is excellent, and differences below 1 bit are barely noticeable.
So Canon's latest bodies are all 2 bits above excellent. And they are only 0.2 bits apart when 1 bit is barely noticeable. You are making about way too much out of their ratings. The key thing to remember here is that DXO is talking about MAXIMUM sensor performance, under tightly CONTROLLED conditions with PERFECT light. Then they go on to completely define exactly NONE of these parameters.
What YOU get out of a camera depends on what YOU put into it. Composition, framing, lighting, exposure, lens choice and processing skills mean a lot more to your photographs than anything DXO can measure.
Give me adequate tools and I can do an adequate job. Give me perfect tools and I can still only do an adequate job. A better camera is never going to improve my photography. If Canon could get the shutter lag and ISO performance of a 60D in an SX50HS, I'd sell my DSLR stuff and never look back.
Dedicated APS-c shooter. Gripped 60D, 60 2.8, 10-22, 15-85, Σ70-200 OS and a big white something or other! Plus a 5D w/28-75.