The D-200 is compatible with AI and AIS lenses while the D-70 won't meter through them. The D-200 has 10 million pixels to the D-70's 6 million. Next year there will be a D-200 wi-fi option to transfer pictures to a computer without using a connecting cord. None of those seem particularly compelling reasons to switch cameras UNLESS the AIS lenses are sharper, or more contrasty, or better in some other way, than the D, G, and DX lenses one uses on the D-70. Nikonimaging.com has MTF charts on most of their lenses but none on the AIS manual lenses. Are we missing out on something by not using AIS lenses? Do professionals use them? Why is Nikon being coy about not publishing lens tests of AIS lenses?
It really depends on the type of shooting one person or professional does. As a regular consumer the D200 is not a practical upgrade uless you have the pockets to do so on just a whim. However, for those wanting the camera for professional use, it is a very affordable alternative to using the D2X which is more than twice the price of the D200. Pixel count is not even an issue nor a selling point for a lot of professional photographers. Let's face it, the D70 was not meant for professional use, more like a semi-pro consumer camera. Now you have bridge that spans the gap between the D70 and the D2X.
I see you are still on a rant about the AIS lenses
Why not ask your local professional photographer and have a discussion about AIS lenses? You can email Nikon about the AIS lenses as well.