Much more fun than Sphere of Influence: IMHO. Two steps above.
You may start as a Daimyo, or down every level to a Retainer. Also, All castles can be built up to be huge castles if you have the time and the resources, no more big castles and useless fortresses. When you become an Army Corps leader you can more or less decide to declare independence when you want, and Castle Lords can be made to switch allegiance by plot so from time to time we see a castle Lord change to another daimyo.
The game is much less predictable now, even with Events. Currently playing a Shimazu retainer, from 1534 we are now in 1552 and we have not yet conquered all the Otomo. Both the Mastudaira and the Oda have been swallowed... by the Asakura. The Hatakeyama, the Suzuki, and the Satake all thrive, while the Hojo are still held in Musashi.
Plus, there is now an Event editor so we may create our own events.