It currently takes 6 full policy trees in this mod (5 in vanilla). That is impossible for a large empire, and takes a very long time for a small empire.
I was playing a Persia Conquest game on Emperor with v7.2.1 when you posted this. I was at about turn 250, and headed for likely failure due to having fallen far behind on Science, following Thal's advice and not building a NC early (!). In fact, I had given up with two capitals in the bag, two toughies left on my continent , and massive Siam and France on solo continents of their own. I was playing only to see how high I could promote a Chariot Archer (3 shock, 3 drill, March, Blitz... and ultimately Modern Armor).
I then decided to switch over to a Culture win. At the time I had nine cities, but SOW gold had me getting a new SP every 5 turns or so. And what trees had I started? Liberty, Honor, Autocracy and Commerce, naturally. No Tradition or Freedom, and not even Piety, because I never have serious happiness problems warmongering. In other words, none of the Big 3 Culture trees.
Freedom was off-limits due to Autocracy, so I aimed for Order fifth and Piety last. Remember, I was still potentially warmongering, now building bombers and researching nukes. My first problem was that Siam built the UN and was gunning for it. I staved him off in one vote, but was going to be nipped in the next. I then allied with enough CS to temporarily forestall a Siamese UN win, and declared war. In the process I denounced him, forgetting that we were Friends. This led to my neighbors Arabia and England - each with armies twice my own - to declare war on me a few turns later.
I quickly rushed Military Bases in my two English border cities, and had them pay off when one was immediately nuked. Luckily for me, this was the only nuclear hit I took. Over the next 80 or so turns I cranked out nukes, thinning out the English army and major cities, while playing defense on the main front, and liberating Songhai cities and CS in my rear. Siam never got close to a UN win again, and I had no problem holding off the invaders. What made it hairy is that England needed only one more SS part to win. I made peace with Arabia, England and Polynesia just before winning on turn 331 in 1912 with a score of 2342.
By the end of the game I had 12 cities (second to Siam, but I could have had 15), 113 happiness, the second most land, and still only the fifth biggest military. The game was a blast, of course, but again I want to point out how much happiness and gold* I had. Combine this with the very high culture, and you may see the concern I have about the cumulative benefits of the warmongering policies.
* My gold would have wound up at about 15K had I not twice invested in winning over angry allies. I learned that a few thousand made them go to blue, but no amount of additional gold made them allies. This may be a bug.