While you are correct that there has been quite a bit of wishful thinking (10 frames per second for example) - I am pretty sure most understand the realities of production cost and differentiating between classes of cameras.
For the most part the D300 diehards are very satisfied with the D300/s and they really just want an up-to-date sensor with respectable Noise performance, dynamic range and the same basic functionality (frame rate, buffer, controls, and body style) that we already have in the D300. Every camera, except the D4, that Nikon has released recently falls short in one or more critical specification - most notably frame rate and buffer.
If they had just give the D800 7 or 8 FPS in DX crop mode it very well may have attracted a lot more D300 shooters. Nikon purposefully chose to keep the frame rate low even in the (15 MP) DX crop (we know more FPS is possible because canon already does it, since 2009, with an 18 MP sensor) indicating that the D800 is not intended as an upgrade path for D300 action shooters.
>> “...a camera as you describe would still have a lot of people screaming.”
Long time Nikonians know from experience that it’s impossible to describe a camera won’t have a lot of people screaming.