Yeah the D300 only had 2 more megapixels than the D200 but there was also the dramatic change of going from a 10mp CCD to the 12mp CMOS. So I wouldn't say it's the same thing.
Unless Nikon can make the 14mp Sony sensor as good in the dark as the D3 then a 2mp increase ain't gonna do it against 18 and 20 plus megapixel competitors that are cheaper in price.
Remember that the D2H had an "awesome" LBCAST sensor too but at only 4mp it didn't stand a chance against other cameras with 8 and 10mp.