So now we spent a bit of time on it what does seems the best strategy for this game? It's a lot easier in my opinion to go full autocracy , fist and enforcement , then rush light tank design and later mixed formation infantry+tanks+artillery. The tech isn't king in this game,going to full mind doesn't work for me . I noticed you get ton of militia but with 40% combat bonus fist gives they are just as good than regulars and ultra cheap, its a massive avantage that bonus compare to a 50%+ research . Better to have numerous inferior troops you can encircle with, very fast and early, even if its the shittiest infantry possible encircle= death. I have yet to really need to produce end units like monitor tanks, nukes or walker.The units i produced at the begining now have ton of xp and tearing apart anything.
I like Meritocracy, Government, Mind. Though I first aim to get 1 level of Commerce for private economy bonus and private investment stratagem. Helps you a lot to get light industry ASAP and if you are lucky enough to have eager industrialist card or two to upgrade it... with free market you can be getting over 200 IP for free PLUS tax money PLUS even more investment into private economy very early into the game. Later on with your own industry and various production buildings public economy bonuses become much more powerful. BP production bonus is also great.
Meritocracy offers nice all around bonuses to pretty much everything though again early on you may want to invest into something else since first level just gives you diplomacy rolls bonus and Recruit Talent which while fantastic you will need Interior Council before you can even use it so very early game it just isn't that great.
Mind while I agree doesn't actually feel in any significant way stronger than other options I still prefer it. Research bonus is self explanatory, cultural adjustment bonus is great too though. Let's you integrate conquered cities faster and recruit their population into your armies that much sooner. I also like artillery and mechanized forces and you get stratagems for them here.
I mean just look at that. Why would you ever want to use unarmed truck instead?
As for quantity vs. quality argument. Depends on situation/terrain IMO. I've had issues on some fronts where logistics were stretched as much as they could be and while in theory I could send more units there in practice it would do no good and just create even bigger issue with supply (there are also over-stacking penalties). Tech can help you not just to increase fighting power of your units but also decrease their logistic footprint.
Here is my medium tank from my current game. Pay attention to fuel consumption.
Here is brand new version of it.
See the difference? Now I can operate twice as many of them out of same number of logistics points. That is HUGE. All it took is few turns of BP investment into Fuel Efficiency tech by Applied Science council (BTW get it fairly early, there are some really strong bonuses you can get there at relatively small investment, I initially made mistake of getting it late because I sort of assumed it's more of a late game repeatable tech stuff like in other games, you know just a research point sink after you finish tech tree for some small bonuses here and there, nope bonuses are actually significant and getting them to 25-50 points is very cheap actually, it does slow down a lot if you try to max them out though).