It's good to know that you now have some appreciation for the all the angst surrounding the D400 . It can be very difficult for all of us to intuitively understand all the various needs we all have. I don't personally need all the things people want in a D400 but I think I have some appreciation for the reasons they need those features.
More importantly, regardless of how I feel, I respect the fact that someone is losing a feature *they* deem important. That is all I have to know.
For example, although I am very happy with the D300/D700 body size, it is not a deal breaker for me. But my hands are on the small side so I very much appreciate why bigger hands might feel differently.
I think I could accommodate 5fps on DX, but not on FX. But that is only due to the unique combination of subjects I shoot. Even if I didn't need 8fps on DX I well understand why some do, and it is surely a personal subjective call, even if we are standing side by side shooting the same subject.
What seems to get lost in the endless D400 debates is that the mere fact that D300 users have to give up so much is a big problem. I never had to go backward before, and that is why up until now I've been, for the most part, a very satisfied Nikon user. And I've run through 5 bodies in 8 years, and never really had to go backward like I would have to do now.
And we would be paying good money to take those steps backward!
(And in truth, I am not exactly sure how much I might miss that 8fps rate- I haven't had to shoot that way since 2004! All I know for sure is that 8fps works for me, and 5fps may or may not!)
Most D300 users are in the same boat- no matter the details of their body upgrade path, they probably never were forced to go backward. And that is the root of the problem. The details of the reasons are purely in the eyes of the beholder.
What gets lost in the debates is that we have many people telling other people what they need. I don't believe any of us can do that, for many reasons. Even among a narrow group like birders for example, we may have quite different priorities and specialties.
The above is not directed at you in any way. It is just a general observation of the state of situation, and not just here on Nikonians.