Re: China's next tank?
That's going back to the early 1940s with the 'Blitzkrieg' concept which was eventually overwhelmed with much heavier weapons.
But the German tanks were the best armored tanks in the war. Even the next best tank that allies {russians} had in T34 wasn't very armored. The only weapons the US had left was to basically carpet bomb german formations. I think the main problem is that tanks aren't tailored to be used in urban fighting scenario. This is not the main task of a tank. A lot of US tanks are in disarray as too many miles have been put on them.
I don't think we really know about the capability of challengers as brits are deployed in the rather peaceful southern iraq. We would have found out "if" the brit tanks had been deployed to anbar or diyala province. I remember the brits had the problem of their air filters being clogged by the desert sand so there goes their operational efficiency.