One of the gazillion things that is fixed in the final game

Perhaps you should not read beta-AARs, they seem to cause you too much stress
I'm also astounded by this AAR. I mean you don't talk much about the specifics of the wars (the first one with Austria and then the second with France/Austria) but it seems like it is too easy. How can you pull off beating those without even breaking a sweat? This all seems too easy, I'm hoping the final version is a bit more challenging.
I've never had problems agaisnt AI armies in Paradox games. I like fights, and I like to figure out how to deal maximum pain with as little pain to myself as possible
After Early Railroad and Medicine I focused on the military techs. Prussia has nice military tech at start, and gets a boost on researching military, so I had the technological advantage all the time.
Boosting Tactics and Organisation up was a priority. Tactics keeps the armies alive, and superior Organisation makes the army stick around without routing (in the big battle against the Austrians, my commander at the battle at first glance doesn't appear that great, but he had the +20% Organisation, which proved to be the deciding factor in that humongous battle

). Once the enemy was routed from battle, the Cavalry Guard (which I most of the time kept in reserve just because of this) gave chase, because hitting somebody at zero organisation on first day of battle makes the army surrender.