Even China, which is officially on one timezone, has local "un-official" timezone.

That's very interesting, I had no idea. Could you elaborate?

from: http://en.wikipedia.org/wiki/Time_in_China

Ürümqi Time (UTC+6), two hours behind Beijing. Although this is not officially recognized, it is the time observed locally by most residents.

And in Russia timetables on all railway stations throughout the country are Moscow time. Even in the Far East regions.

It's true that 8:00 can be considered morning, but I think that's useful in fewer situations than one might think. You can't know, for example, whether I'll be at the office anywhere near that time so you'll still need to ask if you want to get a hold of me.

your second point seems interchangeable with the difficulty of knowing what timezone some random location falls into.

i think it might be slightly worse in that "solar noon"-zones would stick to straight bands.

Yes, it certainly is. But combined with the first point, it explains why such change just won't happen (unless something really extraordinary happens).

When I think about it, I find it quite depressing how many nice things are out there, we just can't have because of overall human inertia and reluctance to accept any major changes.