I generally agree - there is little reason to go back into CNX2 unless it is purely workflow driven. For example, you might want final crop and sharpening for final print to occur in Capture as it provides nice support for multiple versions - and even better if you want all your final images to be NEF files. But generally speaking, the less often you have to change products the better.
I find both Lightroom and Capture individually handle 95-98% of my editing needs. Each has small gaps that are better handled with alternate programs. I have not tried a side by side comparison with Aperture, but would expect Bill's experience is similar - that it handles 95-98% of all needs.