I have a feeling we might be in a tail-wagging-dog situation. Are you really saying that you have outgrown the D200?
Having read and re-read your OP a few times, I have to conclude that what you postulate is this: you want a camera to do your technical thinking for you whilst your mind is focussing on the aesthetics of the game.
For what it´s worth, and from a pro perspective that started over half a century ago (wow! how to depress myself!) and as a fellow D200 owner, it is a pretty bold man who can claim to have found his D200 not quite good enough. Somewhere along the line it seems to me that the balancing act is falling apart.
For a start, if you imagine that great photography can be done in the manner you suggest- the camera thinking for you, then why not just buy the most expensive one on the market and you must, by that logic, be guaranteed the best photographs in the world. I can assure you, it don´t work like that! I´ve had the ´blads and a few of the 6x7s too and believe me, none made me a better photographer. I am currently working on some of my early pro shots - a Bardot film location shoot in ´66 to be precise, which was produced with an Exakta Varex 11a, the heads shot with a Schneider 3.5/135 which wasn´t even automatic stop-down, you had to focus wide open then move the thing to the pre-set aperture. Slow, but the quality of that lens is still up there with (if not better than) my second Nikkor 2.8/135. So, what is better with the new? Apart from the auto diaphragm, not a lot. It is still a manual lens and I wouldn´t look for an AF one.
The D200 stands very happìly alongside any of my old pro-days kit; unless there is need to print over A3+ I see no need for change to anything else. The metering is very accurate and the ability to get in between shutter speeds is pretty cool too - how much more accuracy is possible or even required?
You just can´t separate the technical from the artistic as you suggest. Every part of photography depends on the understanding of, and ability with, the other parts.
To desert the D200 would make sense if one were going FF, in which case, at least with the new D3, you get the full use of any old lenses you might already own in the system along with, according to some, exceptional low-lght opportunities. Faster focussing etc.: for what, exactly? Is anyone´s life that full of HC-B moments?
It´s very easy to get caught up in the upgrade race, but I think that the only people who get anything real out of it are the factories and the shops. In the choice you are worrying about, I´d suggest stay with what you have. However, it´s your money and your mind you have to resolve - good luck!
Ciao - Rob C