Yes, a big improvement, and gen 5 is close, but Arri is still improved.
It's more colour, and colour tracks more naturally.
Look at the shading on the forehead above the right eye (our right) compared to Gen 5, the Arri has more colour and more subtle, but, of course the Arri is a low resolution large pixel camera, so a pretty good trade off to get 12k. Also look at the blemish next to the nose in the left.
The Arri image is more enjoyable as can be felt looking at it, but can be "seen" when looking for why you feel that. But these are areas easily improved once you see it. An expert viewer and see'er can pick these areas of improvement up. I imagine Arri being a classic cinema company, probably employs such people, because you view the colour work on film before digital cameras, you can see that they must have such people, even if they are engineers or colour science.
But what is happening in this video I just watched, in the 12k. I presume it wasn't shoot on the 12k, but I have seen such footage on the ABC in the past. Notice the blemishes and colourisation. In contrast, compare to CineD's toning: