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 24/2.8 AF-D on the other hand is quite good. I don't have one anymore but I liked it. Sharp and good contrast, except for the extreme corners which can be just a little soft, even stopped down, when used on FX. On DX cameras like your D7000, the corners are not used so this little issue would not even apply.