Just in case no one from Paradox noticed, a very interesting discussion is taking place in the Screenie Discussion (for those overanalytical minds..) thread regarding the size of provinces and the simulation of combat, with special attention to World War I. Quite a few interesting ideas have come up (a few might be my own... *looks the other way*), and I'm afraid they might get lost in a thread that would seem to be mere speculation about the sparse details from the screenshot
And since the game is still early in development, hopefully it's not too late to implement some of them. So someone from Paradox please, please check this out! And a post confirming or rejecting some of the ideas might be nice, too 