The one thing that SF is supposed to fix (I don't have it myself) is the AI spamming your fragile supply lines with expeditiary forces, with no way to prevent it.
I can't tell you how many patch 1.4 or earlier games were rendered either unplayable or pointless to continue when the AI did something monumentally stupid, like the last game I played where AI Germany sent 250-300 brigades of expeditiary troops to Italy, to sit idle on the Italian/French border, while Germany itself was struggling desperately in France for lack of units. Eventually,the badly outnumbered German troops were pushed back out of France, and French troops from the Maginot Line broke through the depleted German lines into Germany itself, while the Germans didn't even have enough units on the front to establish a continuous defensive line. Meanwhile, Italy sat nearby with over 100 divisions (mostly German) doing absolutely nothing.
In another 1.4 patch game, playing as Hungary and assisting in the invasion of the SU with about 12 Divisions, which was actually proceeding far too smoothly, Germany suddenly spammed me with over 75 divisions, half of them armored, and all of them dumped squarely onto my fragile supply lines deep in Russia. That effectively stopped my forward units cold, as the stacks of units behind them intercepted and gobbled up every supply that I sent, and far exceeded my ability to produce enough supplies to feed and resupply that many units at that distance from my capital. In short, my national supply stockpile dwindled from 30,000 supplies down to about 2000 in a matter of days, while my front-line units not only stopped dead in their tracks, they ended up dead as soon as the first marginally-effective Soviet units came along.
Hopefully, SF will also prevent the AI from launching hilariously stupid amphibious invasions against distant places that can't be supplied, like Germany invading India, while UK controlled both Gibraltar and the Suez canal, and had decisive naval superiority to prevent convoys from sending regular supplies. As the troops in India starved, and their combat capability decreased, the AI decided that the best solution was to add fresh troops to increase the total combat strength, resulting in still more starving troops. I spotted at least 4 or 5 Transport aircraft flying back and forth across the Balkans and Middle East, attempting to ferry a pittance of rations to the hundreds of thousands of starving Germans. Eventually, right before I quit the game as "pointless", Germany had a total of ONE division left guarding the entire "Russian Front", and about 5-6 divisions in the West. Everything else was stuck, out of supply, in India. Oh, don't forget the frequent amphibious invasion of Finland by Japan.....
