Thanks very much for everyone's input. There seems to be agreement that the D7200's advantages over the D300
include a better dynamic range and much improved low light performance. While the build quality is fine, the small size of
the D7200 is may be an issue for some people. Also, Shun pointed out that the D300 does not have a backup memory
card slot. He also said out that if one doesn't like the handling (e.g. smaller size) of the D7200, the D500 is an alternative.
I would just like to mention that as someone with back issues, lugging around heavy FX equipment would put me in
permanent physical therapy. Hence, my need for DX equipment. Also, as far as wide angle landscape photography is
concerned, Nikon makes a 10-24mm lens, which is equivalent to 15mm on the wide side. (I personally still use the 12-
24mm). There is also the Tokina 11-20mm that Dieter Schaefer mentioned.
Thanks for this extremely valuable information.