I was just trying out this mod. I played Norway on medium difficulty, and it seemed much harder than the Grand Campaign using the same difficulty. Mainly I had money problems, and the Scots were pumping out full armies like there was no tomorrow.
If retraining was easier, it wouldn't be that much of an issue. But it takes ages for me to retrain an army after a battle, since it only trains 2 units per turn. I was basically stuck for 20+ turns because the Scots kept throwing massive armies my way and I then had to retrain them after losing half my army, as the Scots still had plenty of troops defending their cities. They seemed to have a much bigger pool of cash than me, as I was barely able to maintain 1 and a half armies without going banktrupt, yet they were making full armies every other turn and sending them my way it seemed.