I'd love to know this too. I spent a full day playing as Germany and as it got closer to war time I realised that the old usual historical division design template events didnt occur. I had to start all over and redo it so that I accumulated enough army experience to design them. Would be nice if there was a warning for players about this very important change

EDIT - Thanks to the mod developers they've been able to point out that at the start of a new campaign you must go into the Optional rules menu <"Historical unit spawns= "yes"> and that will fix that issue if anyone else didnt know why that was occurring