For minor countries you don't need a lot of political power for any other use, right? I mean, for China it's a main currency - you use it for building slots, for support in provinces, for reforming government, for force loans, for, well, everything.
And actually as a minor country do you need more then 72 provinces (one general/field marshal) covered often?
Yeah, especially if you try to get the"Sun Tzu Reborn" achievement where you gotta grind one of your field marshal to level 10. None of the China's actually have much spare PP so making new commanders to garrison is quite costly.