Nothing too new but some nice features
There is a pro and con for every side you choose for example the pro emperor imperial forces will have easy access to trade with the west and can obtain more powerful units such as Britain's royal marines or American and French forces but their settlements will be more prone to revolt and will be unhappy of the new way of life and modernisation of your clan. whilst the pro shogunate forces will have less problems from civilian unrest and they will be able to get powerful close combat units.
There are lots nice little features added into this game with there being new ways to transport units across the large map such as railways. they have also now added port battles where the defending player can fight off enemy ships attacking the port with new cannon sea defences and your defending navy which is an improvement from previous games where you had to just simply watch your ports being invaded. you can even now have your ships give naval fire support to onshore battles which leads to some amazing battle effects and completely devastates an enemy army if timed right. the multilayer is a nice addition too with new modes and group battles.
however despite all this the games campaign fails to feel different and ship battles are still slow and boring but this game can be picked up for a reasonable price and if your a fan of shogun 2 you should do so.