I was amazed to see the AI occasionally upgrading their Daimyo- they just have to have enough cash, and AI players usually have 0 gold when I play, for some reason.
I totally agree with Oddible's comments... personally, I had no idea who anyone except my closest neighbours were when the whole map was revealed. Why can't we just left click on a city and be told who owns it, like in Civ 2? Argh!