I have 10 Ai, AIs and pre Ai lenses including the 35mm F1.4 that I bought in the 60's and 70's. Yes it is an old design. Not sharp @ F1.4. KR will give you the words and reasons why-others too.
If you want a MF 35mm lens that's really sharp, edge to edge at F1.4 then try a Rokinion/Samyang/ Bower. Less than $500 for Nikon mount and really better than the German branded glass too. It's a large heavy lens that's how they do it. I use it for night landscape photography at F1.4 and infinity.
I looked and looked at so many high priced lens reviews with words like these "...sharpens up when stopped down to F2.0 and F2.8..." F1.4 lenses not so sharp at F1.4? The Rokinion is very possibly the best value in a 35mm lens that's sharp at F1.4. That's if you really need it and can nail the focus.
CAUTION it's very, Very VERY difficult to get critical focus at F1.4 with MF. And, yes I own it, and a lot of other gear too, because Ken Rockwell piqued my interest.
