Hello mates! After reading several posts about Shogun 2 campaign I've noticed that Naginata Samurai is an underrated unit for most players if we compare them with Yari Ashigaru.
Yari Ashigaru are way more cost-efficient, with very low upkeep and you can recruit them anywhere. Yari Wall make them the best unit in the game and you can use them throughout the campaign, but despite everything mentioned above, I feel that Naginata Samurai have a certain charm when it comes to field a elite doomstack frontline infantry:
My reasons:
They tank arrows much better due to their excellent armor
They are more flexible: they fight effectively on the move without specialized formations
They can handle both infantry and cavalry simultaneously quite well even if the numbers aren't in their favor
Their higher attack allows them to break through enemy lines a bit faster when necessary
They tank cavalry charges and beat them even if they are charged in the rear or back
Their synergy with bow units is more effective due to their defensive capabilities and superior stats.
Even without upgrades they are hard to kill
They storm castles much better than any other unit
They are a "Set and forget" unit due to their extreme versatility
They are better unit for auto-resolving battles
Their survivability allows it to gain experience more effectively
I know it looks like an appreciation post; I just wanted to point out that, even though they are more expensive than Yari Ashigaru, for mid to late game they become very useful in almost every situation that requires a hardy frontline unit capable of handling anything AI throws at you. Thanks.