If it meant dropping the 6K resolution, I'd honestly prefer that the XT4 shoot 422 internally over 420. I love my XT3, but I really don't like the 420 color space, especially for grading. I have a Ninja V but I really dislike external recorders. Once you start throwing cages and external recorders onto cameras like these, I just don't see the point. If I'm going to do that, then I'd rather have a legitimate video camera then some awkward, Frankenstein rig with cables, adapters, clamps and mounts dangling off the body. So many failure points. So many things to jostle loose. It all just ends up being a huge pain in the ass.
I think Fuji has absolutely beautiful color science and their lenses are amazing. I'm really looking forward to the XT4. I hope they include 422 on it! I'd take 4k 422 over 6k 420 any day. BETTER pixels over MORE pixels!