Get stuck outside of cities.
Artillery is useless under AI control.
No unit cooperation.
Anti-air/recon unused by the AI.
Unable to transport units.
Will repeatedly transport to useless locales, stacking incredible amounts of units onto carribean, pacific, mediterranean islands.
Seriously. AI garrison control?
Does not use recon units. Fails to deploy AA units correctly, if ever.
Naval units>
"HEY IONIANS I SURE DO LOVE YOU" 1949-forever, british navy
My submarines think they would be more useful in the arctic than actually doing anything. That is what the (broken) strategic pool is for.
No carrier AI. The AI will still build carriers. Hello yugoslavia. Why yes, I do think you should have 6 carriers.
AI doesn't use transports. AI rarely (once in 200 hours) observed landing a naval invasion. AI supply ships do not seem to radiate supply. Supply is already given on a per tile basis. Redundant ship class? Merchant marine can already land in ports against garrisons.
AI will get the vast majority of all ships stuck at sea without fuel. Even ones with incredible range (20,000km+).
AI oilers/refuelers all prioritize the same ship, regardless of range. I do not need more than 40 oilers heading across the world to refuel one frigate when my entire navy is sitting in the middle of the atlantic, out of fuel with the same bad AI.
"What is 'bombardment'?" -Naval AI
Air units>
AI does not deploy helicopters. AT, ASW, supply and transport helicopters are blissfully unaware they exist.
The AI prioritizes falcons (interceptors 4 soft/hard attack) over aardvarks (tac bomber 100~/100~ soft/hard attack) and B-52s for ground attack. In fact, the AI refused to deploy tacbombers or strat bombers outside of the US in my last game whatsoever. Frankly, that is astounding.
The AI cannot use tankers, AWACS, recon planes, or transports. The last one can actually, sometimes, properly supply land troops. However for every 1 that works, I have a dozen either flying over empty waste in Canada or trying to resupply ships. I also have tanker aircraft trying to refuel ships. Neither of them do. In fact, 6 and 4 (respectively) have been trying to refuel this same brooke for over 15 years in my current game.
The AI cannot into rebasing. Period. I even loaded up an alternate save of my current game, and let it run for 20 years while nothing in the world happened. I still had Falcons trying to fly across the atlantic to france. Even though I had built an airstrip in supplied territory in the canaries, and cleared their orders.
The AI cannot into intercepting. They will chase to where they first spotted an enemy, and circle there, ignoring enemies even as they fly right back past them. 200 interceptors continuously circling the German border failing to shoot down a single 1960s soviet jet or even damage is doesn't make any sense. Nor does them rebasing into east germany. They continue to rebase into East Germany, Finland (??????), and Hungary even after I've disabled pathing over neutral territory. I'm not sure how you can even screw this up.
Missile units>
Units do not recognize they have a missile attack, often ignoring it.
Post-21st century naval vessels seem to be able to fire more missiles than possible.
Missiles will reserve as more than one grouping. I had three groupings of cudgels, and none would deploy despite a navy starved of missiles (and yes, the missile size was less than the largest allowable).
Nuclear weapons will often reserve as stacks of 1. That is with autodeploy off and no carriers available. One hundred ICBMs becomes 200+ clicks. How does that even happen.
Fabrication>
The AI builds excluded units. There is no purpose to exclude units if it does not exclude them. It does not attach any build priority to favorited units.
Autobuild gets stuck on, off, on, off. AI autobuild will build nothing but one type of unit. Every third world country has nothing but mountain infantry. AI autobuild is useless, because I really don't want you to build a million combat engineers when 20 light infantry will be done quicker and will do the job much better.
100 fabs, 96 will start construction. 4 will sit forever in queue.
Fabrication options has no discernible effects. AI still building oodles and oodles of combat engineers and mountain infantry, depending on country.
Technology>
Techs that do nothing.
CRBN/NBC.
Pollution anything.
Power gen+/production+ techs do not register in interface. It's nice that I now have nuclear power, but I'd like to know what its actual output is.
Techs that do nothing. Again.
Techs that do nothing except unit pre-reqs. Except that I have never found units that use these techs.
Techs that claim they do things, but are really only pre-reqs for more techs that don't do things.
Techs that do nothing
Production>
tl;dr: Build more industrial goods facs to build more oil wells to build more coal plants to build more coal mines to build more agriculture to build more fresh water plants to build more industrial good facs. Did I miss a part there?
Production cost is not affected by GDP/c. No matter how much the game says this is true.
Produce a surplus of petrol and fully-supplied industry still lacks it. What? Yes, there are roads. Yes I fiddled with the domestic price. This is just a game bug, but a surprisingly common one, appearing in more than 3 games.
Taxes/economy/money>
All those tax sliders are complete bullshit. Social security, too. Culture rating does nothing.
Environment. Environment. Environment. Environment. Environment. Environment. Environment.
I got an event twice telling me that guerillas rose up, so I should increase my cultural rating to improve the region's loyalty. Yeah. The hardcoded loyalty. Uh-huh.
Other>
Game speed. 200 hours = 60 years. One playthrough. That's actually several games, so there's the first 2-3 years where everything runs at a reasonable speed.
All these numbers that are not indicative of anything. Unemployment. Population.
DOCUMENTATION
Strategic pool>
Does not save 25/50/75/100 force button, despite displaying otherwise.
Does not target industrial centers.
Does not target population centers.
Does not ensure destruction of military facilities, even with more than enough ordnance available.
A good chunk of the planes armed with nuclear devices will simply fly towards available friendly bases only to crash halfway there.
Subs will not visibly fire nuclear-tipped missiles. I reduced my strategic pool to a single sub and 6 nuclear tomahawks and watched it. The missiles appear to have simply vanished. No attacks were registered on soviet soil.
SPACE ANYTHING>
lol
Space race indicator is broken.
Buildings that do nothing.
Buildings that say they do things, that do nothing.
Satellites that don't actually exist.
Events that fire (FIRST SATELLITE) even if the opposing superpower has a man on the moon.
Supposed to increase influence. Who knows if it ******* does, because there's not noticeable effect.
Sphere>
Seriously? You can throw money at contries and it doesn't increase relations nor sphere nor does sphere ever seem to shift even for countries that have ever reason to shift spheres. I slaughtered western europe as the US and denmark remains my buttbuddy.
?This mechanic is fundamentally broken. Are you even trying?
Other>
Events that reference things that aren't possible (+culture for loyalty!!/first satellite)
ECM/stealth/techs that do nothing
North Korea rolled every ******* time.
Millions of troops pouring into Vietnam in 1950 from every western country, damn the losses
China getting into an all-out war with France with every NATO member in existence sending the vast majority of their troops. Every. Time.
AA defenses. No firing indication. VERY rarely seem to actually shoot anything down. No indication of effectiveness or stats.
Numbers that mean nothing. Population. GDP/c. Individual taxes. Social spending.
Techs that do nothing.
I can't think of anything else right now. I'll be sure to post if I remember anything else. All that's left is to ask why? Why would you ever put a game out in this broken state, with half the features missing, ingame interface lying through its teeth, mechanics that don't work, AI that doesn't play its own game, and unoptimization out the ass (Did I mention the game speed?).
Why?
We all hope that a long wait for update means all those broken things are gonna work now. Are they?! 
Please 