Thank you for your response.
If making two manpower pools is too hard, then limiting the number of frontline citizen divisions the Draka could build, and if at all possible checking against the number lost both as divisions, and manpower can perhaps contribute towards an increasing Serf revolt chance? When I find the time to finish my current game, I'll likely try a playthrough with Draka to see how they're handled. One thing that can make them tremendously stronger than OTL is building and using theri best citizend divisions through regular manpower, when those sould be both limited in number and relatively sensitive to damage compared to Serf divisions.
As far as events go - that's merely an observation. First you indeed should concentrate on the gameplay and get it when you want it, before bothering with introducing more of them. While they can change the game a lot and spice it up, they have the potential to produce a lot of issues that have to be tracked down and dealt with as well.
Interesting events might be the OTL Draka attempt to bait Nazi divisions in the Balcans and cut them off, or the massed air-borne assault that allowed them to shatter the German defensive lines in the Caucauss in the books. However, I have no idea how feasible that will be, unless there is a late game-start options that begins shortly before the war between Nazi Germany and the Draka, with pre-determined borders and troop postions. Without this, its something that a Draka player might do, if feasible, but I don't see the AI managing organically.
Then again, it was a boon that much of the fighting against the bulk of the Draka army happened deep in Russia, with lare provinces and low infrastructure slowing down their advances, while allowing me to shift reserves and air-strikes against organization. Otherwise, the Draka AI might have managed a massive encirclement in the East, especially in the are where much of the back-and-forth fighting happened.
They were able to create a whole new Draka superior sub-Species for the final war a few decades after WWII, alongside genetically modified shock-troopers, on top of everything else. It was also a Draka bio-weapon that allowed them to feasibly execute a successful first strike against the Aliance of Democracy, thus winning the Final War on Earth, though at a high price. So in that regard, they were even more advanced than usual compared to everyone else.