I'm going out on a limb here and thinking that your perceived difference between the EF 85mm f/1.2L II and the EF 85mm f/1.4L IS is not the difference between f/1.2 and f/1.4. It's the difference between designing a lens with enough flat field correction to do well shooting flat test charts all the way to the corners (because that is what is required these days to sell large numbers of lenses - no matter the intended purpose, a new lens *MUST* be sharp in the corners when shooting a flat test chart or most buyers won't even consider it) and designing a lens with enough field curvature and maybe a bit of spherical aberration to give pleasing out of focus areas at the expense of less than perfectly sharp corners when shooting a flat test chart.
If I had to bet on the RF 85mm f/1.2L, I'd put my money on it looking a lot more like the EF 85mm f/1.4L IS than the EF 85mm f/1.2L II.
I haven't tried it yet, so you might be correct about the rf 85mm 1.2; however, the RF 50mm f1.2L is everything I could wish for in terms of rendering, character, draw, depth, punch, dreamy, creamy magic. (Sorry, these adjectives are as technical as I can get.)
I feel the same way about my
ef 35mm f/1.4L II as I do about this new RF 50mm lens--it's just absolutely amazing.
The ef 85mm f/1.4L IS just doesn't have quite the same appeal to me personally. It has decent bokeh without busy, "nervous" out of focus areas; it is slightly sharper than the 85 1.2L, and it has good IS. I couldn't even say for sure that I'm seeing it objectively, but it seems no matter the light, its images just don't have the "glow" I'm looking for in skin tones and backgrounds.
I'll look a lot of sample images, read reviews, and stay tuned here before pulling the trigger on the new 85!