I agree that the D7000/D7100 do not meet the needs that brought people to buy the D300/s . My D300 still occupies first position in my bag given that my prefered venues are "run and gun" style shooting. I have a D7000 with grip that hasn't seen action yet but I already know that it won't fill the role my D300 has.
A D400 equivalent body is the only thing that will move the D300 out of my bag. I do not earn sufficient funds from shooting to justify the investment in a D4 nor do I really want to carry a D-single digit body when shooting.
When the D300 eventually goes south I will make the best financial decision available at that time. If that means switching over to some other vendor, that is what it means. I am not too heavily invested in Nikon glass and most of it will work for FX.