This game has some serious problems in an attempt to simplify/fix the problems of Nobunaga's Ambition series, but for every problem it fixes it creates a worse one in its place.
First, the internal infrastructure of Souzou is... different. You've a stupid amount of castles and mini castles that you got to build up infrastructure in roughly 4 levels (land, structure, expand land, and roads). Unlike the previous NAs where you either have your infrastructure doomsday team finish everything in 2 months, or you have your faceless guys queue up 3 years worth of infrastructure projects and then check back in 3 years, here you're supposed to constantly check what all your 20 to 200 places are building each month. Don't worry because you can delegate it all and that's what you should do for your sanity, and like the previous NAs you'll have resources you can't possibly spend after about a year or two worth of game time anyway.
In an attempt to curb down the previous game's ridiculous million versus million army matches, Souzou made it awfully hard to amass your army with both in game restrictions and a rather unwieldy interface to move troops around. Besides, by the time you actually have troops that you can call up from reserves, you're already well on your way to winning the game so it's not worth the time to navigate the interface to move your troops when you can just delegate for a few more months and have AI kill everything for you. It'd be far faster in real life time to ignore your massive army in a safe location and just build a new one from a scratch. Due to the game's rather cryptic rules on how many units can stack when you're doing siege, you're probably better off just moving your leader to a corner of the map and delegate everything else to AI who at least will never run into a situation where you can't even move your army due to stacking rules since the AI knows all the stacking rules way better than you.
As is in this game about all you have to do is build the first few structure that might actually matter (like stuff that increases your troop's power) and plot out the first couple of fights where you're not strong enough to steamroll everything, and after that you should just stop playing the game and let the computer play for you. Yes the previous series have this problem too, but at least before your key units feel powerful so it was okay to play only one city with 3 or so major units while the computer supplements you with hundreds of your units, because the powerful units can wipe out entire armies by themselves. While the strongest generals are still strong, their effect is not nearly as pronounced and if you've any interest in finishing this game in a reasonable time, you'd be much better off taking Nobunaga or Shingen or Kenshin to a backwater corner of Japan to work on farming so that you can have as few city under your direct control as possible so that the computer can do all the ridiculous amount of micro management needed in blazing speed. Sure, you can do better than the AI if you take the time to figure this out, but it'd take literally 10 times longer for you to execute these commands as opposed to the 'delegate everything to computer' command, and they can still win just fine once you setup the right foundation for them.
Given the dearth of good strategy games in Steam, I guess it's still worth buying compared to other options that are available (provided you can read Chinese), but compared to the other games of the same series or Romance of the Three Kingdom, I can't recommend this game if you're able to get any of the earlier NA or ROTK games instead.