Well from a historical perspective the 1545 vanilla campaign has quite a few historical mistakes.
The Uesugi clan didn't rule Echigo in 1545. The Nagao clan ruled Echigo! Uesugi Kenshin was known as Nagao Kagetora in 1545. It wasn't until he inherited the Uesugi clan in 1551 that he changed his name to Uesugi Masatora. Also the mon CA has given the Uesugi clan is incorrect. If you want to take a look at the correct mon then take a look at the Ogigayatsu mon(The Yamanouchi-Uesugi and Ogigayatsu clans were branches of the main Uesugi clan). CA has incorrectly given the Uesugi clan the Bishamonten letters as their mon. The BI letters were used in one of several of Uesugi Kenshins personal standards.
The Asakura clan ruled Echizen, not the Ikko Ikki.
The "Hattori" clan did not rule Iga. A Ikki "Mob" Republic ruled Iga.
The Tokugawa clan was known as the Matsudaira clan in 1545. It wasn't until Matsudaira Motoyasu(Ieyasu) petitioned the Imperial court for a new name in 1567 that the clan became the Tokugawa clan.
There were no mass formations of "Katana" units. The primary melee weapon of the period was the spear..
The Hatakeyama clan was not one big single clan. But its branches were indepedent of each other and thus should have been divided into three clans.
CA has not included the Ishiyama Hongaji temple/town. Since the temple was the headquarters of the Ikko-shu and were a powerful faction in the Kansai region.
Just to name a few..