I disagree. By the end of the second livestream johan only reseached 2 air doctrine, 2 naval doctrines and 3 land doctrines.
Besides that the tactics being unlocked, being the biggest benefit of doctrine research, wont give you any advantage if your generals are bad at combat and dont choose the right tactics for the right circumstances. Its basicly theoretical doctrine research, while your generals need to develop the practical usage of them in game. An army which developed advanced tactics in an war wont benefit largely from it if the general is an rookie.
In regards to advances in theory, if you're not fighting a war its very hard to establish if the theory works or not, and its hard to work out where its lacking and can be improved. This is because you're lacking the feedback from the front lines that occurs when you are at war. I think HOI3 was on the right track with land/air/naval experience increasing the rate at which nations could research doctrines.