Re: Shogun 2
In response to your queries , in the mentioned order:
1) It's a great game, as for whether it's the best strategy game...that will be a point of debate. But it is a great game , no doubt about it.
2) Shogun 2 is set in feudal Japan. You'll only have Japanese units but each clan has their own specialty. Some clans offer bonuses to naval units, others to infantry e.t.c
There are some DLCs too for the game which offer new clans with unique units. I hate how Total War 2 is going the DLC route :/ .
3)By Skirmish mode , I presume you just want to setup custom battles? Yes it's available.
Shogun 2 places a lot of emphasis on politics and espionage. Assassinating a high ranking general just before a battle can greatly turn the tide. I remember doing this in Medieval : Total War. My smaller army with an expert General was able to defeat a much larger force (winning against impossible odds results in a victory called "Heroic Victory")