Part of thew problem is that Nikon doesn't want to admit it but many pros use the (D300s class)D7000 and (D700 class cameras) depending on the job. Many pros do need or want 36mpx for large printing, cropping, detail rendition etc and the D800 will fit that pros need. Also amateurs, and wealthy people who really don't know the truth about mpx will be more inclined to buy it because it will be "better" in their eyes.
It also seems to be a jab at the Canon 5Dmk2, sony a900/850, S2. Nikon knows that both the a99 and 5dmk3 will have tons of pixels so they will probably put an astronomical pixel count to top Canon and Sony (although it has a possibility of sharing the same sensor as the a99)
The crop mode should be between 12-16mpx which is perfect for me... So you don't need to use all of the active pixels...
In addition the camera is probably going to not be as good in low light (and the burst does really suck) so it won't be direct competition. These specs aren't verified and announced anyway so they may be different (although NR usually is right)
Wait it out, and if you don't like it get a used D3s...
Who says a semi pro may not need 36mpx. I am a semi pro but my level of work is at an Advanced fulltime pro's level (like many part time photographers)... In my line of work 10 or 12mpx is enough but for another it may not be. How much money you make off your work (or days invested in it per week) should not determine your shooting level or how pro is your line of work.