My point was that if you have a time critical application that is very specific (only going to be used in a very limited environment that isn't likely to change for some time) it might be possible to take advantage of speeding the application up by a little bit by using the Native API, but I never meant that it would be a very widespread thing, either.
And as for my comment on how it changed: There are a LOT of differences between Vista and XP, I realize that they are both NT, and so share most core aspects of the Native API, but technically, they could make a HUGE change in the Native API and still ahve it nearly seamless, because almost every program, aside from essential startup programs and deep parts of the kernel use the WIN32 API instead of the Native API, and they can make drastic changes to the Native API and simply use the same WI32 API to wrap it. That way they can modify the underlaying structure of the Native API without affecting most programs. And compared to the work of writing some of those parts of the kernel that are new in Vista, upgrading a couple essential programs to use slightly different Native API calls wouldn't be much work at all.
My point is that the Native API is pretty much invisible to the end user and since it's so low level, with everything above it, it could be heavily modified with very little outward appearance in the WIN32 API. I never said that they WOULD do that though.