Hello.
I have been playing on the 100 player maps since they were released. Each doctrine requires a massive reevaluation of how to play the game, to the point where your doctrine choice matters more than anything else. I will evaluate the strengths of units and the games doctrines. First let me evaluate all the units as a whole. Then I'll break down the strengths of the doctrines. Comintern, Allies, and Pan-Asian all require micromanaging, while Axis can just put units on a path to the enemy or on a defensive position and trust with relative confidence that they will still be there in the morning. Therefore Axis is the best for those that don't play this game 24/7, and is the easiest doctrine to win as. Having 15% attack power AND 15% health is absolutely amazing and a 10% resource penalty ends up being nothing.
Consider all of Axis units. Each one can be extremely effective thanks to the doctrine buff that makes EVERY UNIT better than those of basically any other doctrine. If you want to use anti-tanks as Axis, do it. Want to make tanks, do it. Focus on ships or subs? Do it. I'll show you what I mean:
Militia: Militia are useless in the early game for axis, but great at end game. At the early game you are nearly always better building infantry no matter the doctrine. At end game however, high level militia are very cheap to build, have stealth, and have an extremely strong state baseline. When other units like motorized infantry are starting to take 12+ hours to build, you can count on militia.
Infantry: Axis infantry aren't the best to make but are the best infantry in the game. They have +15% attack and HP. Comintern just gets a research buff so can make higher level ones a little faster.
Moto Infantry: Get a +15% move speed to an already super fast unit. Also get +15% damage against infantry ONTOP of the +15% damage doctrine bonus for +30% more damage! Amazing unit to use as Axis.
Mech Infantry: Honestly a bit expensive to use but as Axis you get them earlier than everyone. Great to use side by side with moto infantry. When level 3 or 4 moto infantry start taking a long time to produce, try switching to level 1 mechanized infantry from the same production plants and you will see that you can suddenly produce capable units for a fraction of time.
Commando: Garbage but still better than anyone elses. They actually do the same damage to infantry as Allied commandos but are better at everything else since Allied commandos have +15% to infantry but axis has +15% to everything AND 15% more health.
Paratroopers: A waste of resources but situationally very useful. I once saw paratroopers flown across the med to take an enemies capital instantly. Yours are the best if you do make them. Sure, allies get +10% health bonus, but axis get +15% and +15% damage!
Artillery: You get artillery available a little later than everyone else at +1/+2, but yours is the best in the game! Pan-Asian gets a +15% artillery bonus to infantry which is great, but you get a +15% artillery bonus to everything!
Anti-tank: Probably your worst unit. This would be on-par with soviet anti-tank, but even though they get +15% to light armor and heavy tank, they get -10% damage overall so they are worse than you.
Anti-air: These units are amazing and have a historical buff against heavy tanks as the german 88 and 105 flak guns were used against tanks in WW2! They also have a +15% bonus to aircraft giving you +30% more damage than any other doctrine and are the ONLY doctrine with anti-air specific bonus. These puppies are good, honestly I build these towards end-game in place of anti-tank. With the city bonus they get, a small stack of them just makes cities unconquerable unless they hit you with artillery fire.
SP Arty: Kinda expensive, and ordinance plants are expensive to get to high level and are limited in what they can build. Allies get +10% to heavy armor and +10% hitpoints. You get +15% to both, lol. They just get theirs -1/-2.
SP Anti-Air: You get these before everyone else, and yours are strictly better! Allies get them 0/0. Comintern and pan-asian get them +1/+2. You get them -1/-2! Nuff said.
Like, do I even need to keep going? Axis is just better at everything. They even have the battleships in the game. Wait, right? BATTLESHIPS? Axis are known for subs, how can they have the best battleships? Pan-Asian has the best battleships right? Nope, their only advantage is that they get them earlier than axis. Pan-asian battleships have +10% health and damage, however that health buff only brings their units up to +0% since all their units have -10%! This means that Axis battleships, with +15% health and +15 damage from their doctrine bonus are actually better than even the might yamato!! Isn't that nuts? TLDR: Play Axis.
Allies: Unit doctrine bonuses:
Allies: Basic doctrine bonuses.
-30% production time.
-25% research cost.
-20% upgrade cost / time.
-10% move speed.
Allied Infantry:
Your infantry are weak, likely the worst in the game. Motorized infantry which are a staple scout unit in this game get an availability research penalty of one day. You get a minor buff to commandos and paratroopers but those are generally luxury units. You get a HP buff to Mechanized infantry and a reduction in unit cost but they are already expensive and take a long time to produce which doesn't make them any more attractive. Your best bet if you need infantry is to just level up basic infantry as high as possible and supplement them with ordinance and air power. Your infantry are bad. Build the infantry you need to take and hold cities and don't get too tricky.
Allies Ordinance:
Your ordinance is all bad, likely the worst in the game. Wait, what? You read that right. You don't get any buffs to any counter-units (anti-air, anti-tanks) which makes you generally rely on infantry alone for holding ground. SP artillery is amazing and you get a buff to it's damage against heavy tanks and it's... uh...health but it is still an expensive premium unit. Would it not be better to just completely forgo investment in ordinance foundries?
Allies Tanks:
Your tanks are all bad, likely the worst in the game. WAIT? WHAT? What can I say, the allies strength is really quantity. They should be swapped with Comintern. Both your light and medium tanks get a research penalty. Tank destroyers are a fun unit to use and you get a 15% production cost decrease and speed bonus of 15%, but even with that speed bonus they are only 5% faster than other doctrines because of your -10% speed penalty! While fun, they aren't really worth it because they aren't flexible enough to do more than defense. This makes your tanks also sub-par.
Allies Aircraft:
Aircraft. Aircraft make up for all the downfalls of your other units. If you want to play as the allies, learn all the mechanics of aircraft. Your interceptors can be researched gotten a day earlier than axis or comintern which keeps your skies clear of enemy aircraft. Then you have range bonuses on tactical bombers and strategic bombers that can absolutely cut down enemy infantry or destroy their cities and infrastructure. Just don't let your planes die on the runway.
The whole power vs. quantity concept.
