Germany was aware that they were facing an opponent in Russia that could lose the entire population of Germany and still have enough national manpower to fill its armies. Germany was aware that their machines of war were complex and slow to manufacture.

Yet aside from a brief time in 1941 when they actually used their famous 'blitzkrieg', they used the prepared frontal attack that was the preferred method of attack in 1915 on the Western Front. As a result, they took losses in manpower which they simply couldn't replace and losses in equipment that would take a long time to replace.

It's not like the Eastern Front in WWII was a continuous trenchline like the Western Front of WWI. There were always ways to go around fortified positions. Yet the Nazis--or rather, Hitler and the cronies he promoted, insisted on attacking right at the Russians.

Even in 1945 in Poland, they try to slow down the Russians by attacking their columns where they were strongest.

The classical aphorism goes: "The country with the prettier uniforms loses."

This is entirely subjective, but the gist of "prettier uniforms" means more baubles on it.

And you're not necessarily doomed to defeat from it, after all, the Russians beat the Turks in 1878, the US defeated the Injuns, the Romans conquered the world. So it only says "the general effectiveness...is inversely related".

And this brings me to my second major change in the rule, "national military". This limits it to after the advent of the modern concept of the nation. This allows for the Romans to kick the crap out of everyone, for the Italians in general to have military dominance in the medieval and renaissance periods, and exceptions for those areas which had no conception of nation.