the whole discussion of whether or not there has been any real change between the 30D and the 5D Mark II is a good demonstration of how different people look at cameras.
for those who purely look at a camera as a sensor, or purely as an AF module, and judge it from there, perhaps the 5D Mark II doesn't appear any different than the 30D. same pixel pitch, same 9 points, etc.
I have owned the 30D (shot 30,000+ photos) and 5D Mark II (shot 60,000+ photos) and they are vastly different cameras to me. from viewfinder size, build quality, rear LCD, high-ISO handling, physical handling, and even per-pixel image quality (judged by cropping 5DII down to the same 8 MP image of the 30D), the 5D Mark II smashes the 30D in every way. I could barely touch the 30D after buying the 5DII, and sold it pretty quickly. I couldn't conceive of a single instance in which I would have pulled out the 30D over the 5DII. so for me, judging a camera as a sum total of all the things that go into making a usable camera, there is a massive difference between the 30D and the 5DII.
whether or not there's an equally large gap between the 5DII and 6D will similarly be up to the individual user. I can't speak even for myself on that, because I haven't shot anything with a 6D yet.