I'll get back to this - I've been digging joyously into Morrowind for the past week, basking in delicious modded nostalgia. That was the result of this LP, though.
I got Nobunaga's Ambition - Spheres of Influence and played the hell out of it for three days.
That lead to redownloading all the CK2 DLC and modding it until I was playing as an Argonian in control of the Summerset Isles.
Which inevitably led to Morrowind.
Anyway, Nobunaga's Ambition is much better than I had thought based on my early experience. It has simple city-building sim elements, a simple Total War style combat, and simple diplomacy, favors, and requests like CK2 - making a pretty damn good balance between all of them.
Here's an run through of the game as I experienced it. I'll grab screenshots offline as I didn't make any of my own just to convey the points I mean.
I started at the lowest rank possible - a retainer substitute. Pleasantly, you have unique artwork for all 2000+ characters, including a few female officers. I chose a dude from around where I used to live - a sort of scruffly looking samurai loosely based on a historical picture somewhere, I expect.
At retainer rank, the map of Japan is pretty useless to you, instead, the game focuses in on a map of the castle town you are managing. It's resource balancing as certain things do better next to certain other things (for example, markets should be by roads but also near entertainment. Rice paddies should be near water but also temples). You can only do so much work per month, so there's a preparation and execution stage. Basically, it's just building in this part of the game. Occasionally your lord will call you in to join a fight somewhere far away, which happens instantly.
This game has missions and goals. So as a retainer of a daimyo, there's a goal all of the lesser lords are working on in the form of missions. Perhaps the goal is "Take Kishiwada Castle", and the missions will be "send 1500 gold to the daimyo", "gather 1800 troops", or "raid Hideyoshi's forces at Osaka castle" if you can do them, they happen instantly. Combats that fail leave the quest open to be finished by yourself or the AI retainers of your level, who will just sort of randomly pick up quests and finish them after a couple months. Your effort on these quests reward you with honor, which eventually pushes you up in the ranks, to different game modes.
Chamberlain, for example just manage a castle - viewed from the world map, they have less direct control but more streamlined simplified versions of resource management. Missions at this rank tend to be more military focused.
When you own a castle and army of your own, you get retainers to do jobs for you (with skills similar to Pokemon Conquest). Anything from convincing foreign retainers to defect to overseeing road construction. Diplomacy gets bigger here, and your daimyo can give you extra castles or retainers if you have the honor to trade for it, and if they're available.
Each level of play has similar elements, but higher up the game is more military focused, as that's the only way to gain land.
When you're in charge of a clan's military effort, the quests disappear because you're in charge. The AI will join up if you start attacking castles. If you defect or start your own clan, the same is true. I didn't unify Japan at any point, but I imagine that's the goal.
Combat is underwhelming, to be honest. It is directly between CK2 and Total War - as CK2 has a terrible system and Total Wars combat is great and basically the whole game. In this, you have direct control over one unit (made up of 4 parts which can only be of 4 types - cavalry, infantry, gunner, archer). Each unit can have up to 3 officers in charge (you and two of your subordinates) which give buffs and debuffs on a timer to activate as you please. Positioning, timing, and reactions are important, which is pretty fun. Castle sieges are snappy enough, but you can usually feel if it will be successful or not within the first few seconds. Ally AI is fine, but won't come around and flank enemies as you would want them to, sometimes even waiting for you to get killed off before heading in to fight... Numbers win the day, it seems - as I just swarmed enemies and stomped my way all over Shikoku when I played with the Chosokabe.
Similar to CK2 there are a few different time periods to play in, but these are all a bit closer together - around 1550 to 1610 across the whole spread. Historically, this chaotic time did have enough difference to make this engaging.
The game is serious, with a larger than life attitude toward history. There's very little dark and gritty, but occasionally it does come up. I don't know how succession works as the game goes month by month, my character didn't get old enough to die. I did get married, though, but didn't have any kids, at least that I noticed...
There are story missions as well, but I didn't get drawn into them enough as many of the main characters of those are also the main characters of Conquest. There's a bunch of extra features like making your own officer, changing all the main characters into cats (from a Japan only Nobunaga no yabou release). Overall, I recommend it if you can pick it up on sale or play it used on PS4 (maybe PS3 too, I forget) if you get the chance. It's a cool game.