It's amazing that no one has mentioned the great "Rounded Aperture Blade" theory in all of this.
From what I can gather, pretty much all if not all L series lenses from the Canon 24-105mm f/4L launched 2005 have rounded aperture blades for smoother bokeh.
The mark II versions of the 85mm f/1.2L and the 70-200mm f/2.8 IS have rounded aperture blades - their mark I versions didn't. The Mark I were pre-2005 and the Mark II's are post-2005.
For portrait work you want the rounded blades. The 35mm f/1.4L (released 1998) and the 24-70mm f/2.8L (released 2002) don't, and they really stand out in their list of fast L lenses that don't. The other one being the 135mm f/2L, but I'd say that would get the rounded-aperture blade update sometime later.
So they will both pick up rounded aperture blades, and will have less CA from improved sub-wavelength coatings.
You can easily check what lenses have what kind of aperture blades on http://www.the-digital-picture.com
- which is where I did all my research for this.
I am uncertain if the 35mm f/1.4L II will pick up weather sealing. The 85mm f/1.2L II isn't a sealed design. I don't think they see the 35mm as an outdoor lens, like the 24mm f/1.4L II or the 24-70mm f/2.8L.
If they get rounded blades and reduced CA, then that's a worthy upgrade, although I'd love the 35mm to pick up weather sealing as well, although not confident in that.