The 28/2.8 AF-D is a rather poor performer. It was substantially simplified by Nikon from the very good manual focus 28mm f/2.8 AIS lens, probably to save costs.
The non-D 28mm f/2.8 AF-Nikkor adopted a 5-element design from the Series E lens. I think "rather poor" is a good description of that lens. (Oddly enough, Canon made a similar decision for its first 28mm f/2.8 EF).
The "D" version used a new 6-element design. It was a decided step up from the older lens, but still not, in my opinion, as good as the 28mm f/2.8 AI-S.
"There is no real magic in photography, just the sloppy intersection of physics and art." — Kirk Tuck