I don't agree with all but perhaps the last line of this statement of his:
"At Normal, exposure is lowered by 1/3 stop. If flash is active, exposure is approximately 2/3 stop lower than normal. If you are a RAW shooter, this starts to be a concern, especially if you aren't a Capture NX2 user"
At Normal, I many times have gotten what appears to be an overexposed image (unless there's some new type of of lowered exposure I haven't learned about). If I "turn it off in Capture NX, the exposure "fixes" itself. That is unless there are highlights that are hopelessly blown out which no software can save.
"If you are using other RAW converter you are going to end up with images that are underexposed. This is precisely the problem for me since I use Lightroom 2 as my main program."
This makes sense. It's often said that NX and NX2 work better for Nikon images. This I can believe to a point. The D300 for example has Capture NX algorithms in the body although optimized for the cameras less powerful processor. Capture NX likely recognizes itself more than Lightroom and other software might and thus might know how to apply settings better in an image. Just a guess on my part.
"My exposure mode most of the time is in manual mode, and sometimes in aperture priority mode, so setting it a LOW won't cause my RAW captures to be underexposed undesirably too often"
It shouldn't at all. I shoot in A mode the majority of the time and M mode was what I used to use. If he's getting underexposed images more often in M mode, which from what he's saying. he is. Then he's not setting his manual exposures properly (likewise, neither was I when I shot in M and got overexposed images). This is one of those examples of "the person behind the camera is ultimately more important than what's in the camera". You have to know how to use these tools and as I've said before, most people don't seem to fully understand ADL.
The lenses used can also have an effect as we all know. Different lenses meter differently on the same camera. For example; my 70-300 often can be kept at exp. comp. 0.0 or perhaps stopped down to -0.3 or so. My 300 primes likes to be between -0.7 and maybe -1.0. My 70-200 really hates brightness. -1.0 through -1.7 is it's favorite and occasionally down to -2.0. here's what I'm talking about:
I shot this not long after I got my 70-200. Almost all of my shots were overexposed this way and it frustrated me to no end. All the camera settings were the same as for my 70-300. The exposure comp. was left at 0.0. I saw no reason to change it and thought the lens was defective. later I read similar articles about ADL doing stuff like this.
This I did with the prime:
Same result. I began blaming my gear even though I hadn't changed anything. Now my prime looks like this:
http://www.pbase.com/shonn/image/109692923 (similar but different species shot under the same conditions)
Before, that ducks sides would have been blown out and horrible looking.
Now my 70-200 looks like this:
Granted a darker bird but I could have still blown it out a little had I not reevaluated what I was doing wrong.
What all of these shots have in common is ADL set to normal. True, wildlife shots will always require some tampering, the degree is not nearly as much as it once was.