What you say is true, but the switch is still a trade off.
Yes, you can program one of the other buttons to perform the AF-On function, but then it doesn't do something else. There are simply less controls on the D7000.
The mode dial does move far to easily on my copy of the D7000. It is also a different method of controlling mode, more in line with the consumer bodies.
The AF is a trade off, yest, you might get better Hi-ISO images, but you focus system might not keep up with sports subjects.
The newer image processor and internal software are not obvious good points. Neither is the smaller size.
I have a D7000, and it suits my needs, but it isn't obviously superior to the D300s, just different. I don't use it when I am shooting sports. Now if it were the so-far-mythical D400, that would be a different story.