I agree “一镜走天涯”is a good solution for travelling. All points you mentioned are absolutely agreed. But some drawbacks
1. image quality. a 10X zoom lens is unable to keep in high quality for all range.
2. aperture.
3. normally no macro.
4.10X zoom increases the complication of the structure, and meanwhile increases the possibility of defects.
5. in case it out of work, you have nothing but body.
I don't use Nikon. No comments for D70s.