FWIW, my minor irritation with the 85/1.8 was its slight CA in some instances, and my major gripe was its clip-on hood, which I found cumbersome to attach correctly; when I didn't get it on right, it would pop off easily.
If I were Canon updating the 85/1.8, I would bring its optics up to current non-L prime standards, add IS (dropping max aperture to f/2.0 would be a small price) and give it a bayonet hood.
I forgot about the hoods. Great comment!
I have the 50 F/1.4 and the hood attachment is terrible -- you can cross thread it, you can miss the ring and have it slide up the lens barrel, reversing it is a pain, it is poorly secured -- you name it.
If the 24/28/35 IS refreshes are any indication, the new hood for the 50 / 85 will be stellar. I have the 28 IS hood and it's as solid as any L hood I own (save for the war-worthy 70-200 F/2.8 IS II). It's secure, fast, and well built. In fact, on the 28mm length, I just leave it on the lens full-time because I don't have to fiddle with a CPL. (I hate wide angle CPL 'pseudo-vignetting' you get from such a wide variation in polarization, so under 35mm length I don't use CPLs.)