Granted I havent been very active lately, but apparently everyone forgot everything I have ever said...
The idea of this game is still, stack bonuses (bonii?).
Are you Italy, or the turk? Then yes get administrative. It's completely pointless to take it as anyone else. -25% Core cost alone is useless if it isnt being stacked with a useful NI. You'd be better off taking Economic and being able to afford better advisors (thus create more ADM, instead of spend less).
Are you Prussia? Then buy all the military ideas. Stack those bonuses and watch 40k prussian troops destroy 200k austrians.
Austria? Well now diplo, influence, expansion, and let your bajillion allies do all the work for you.
Your choices for idea sets should be custome tailored to fit your nations NIs. I would not get the same ideas as Prussia, or Saxony, or Italy. They are all played differently, and your idea sets are there to enhance that particular strength.
Also defensive is still hands down the BEST military set. +1 miltrad = better generals. -10% maintenance cost = 10% bigger armies. Better generals with bigger armies that have more morale will win every battle in every game. The end.
(also, do not ignore the reduced attrition for you, but hightened for enemies. Manpower is everyone's weakness. Defensive is as powerful as Quantity {if not more} when it comes to manpower.)