It's the same thing for all international games. Besides, proper gameplay requires basic english like yes no left right forward attack defend...
And it's easier to refer to technical terms like power strike or masterwork great long axe if everybody knows the same names.
True. Though, I guess it wouldn't hurt at all to have it translated, and what I've personally always liked to see is some more in depth explanation of game stuff in all languages (like the flags, god, I hate to sacrifice my peasant life to defend the flag and then still loose because other people still defend the siege tower entrance), giving translation for in game commands, etc.
I'd volunteer to do some German translations if that's implemented.