Is it worth though ? I mean is there any difference if you choose to increase your peasant strength and receive lots of light infantry against fever, but more efficient heavy knights ? Maybe there is some "secret army composition" that will pwn everything it encounters ?
If there is, I'm sure it hasn't been found yet. You are also a bit limited in how you set these power sliders, because if you let one group go too low you get revolts or (if it's the clergy) pissed of clerics who denounce you with the pope. Not to mention that you can't at all influence the settings that your vassals use.
Your ruling law makes a big difference though... for your demesne regiments, that is... Under feudal contract your demesne regiments are not so useful although their numbers are big while under popular law you get decent infantry and archers, and under royal prerogatory you get good heavy troops. RP is generally seen as giving the best troops. It pisses off your vassals, though.