Just finished a Tokugawa campaign. The strategic position required more stacks than I can finance if I went all samurai, so my armies are based on an expendable core of about 5 yari ashis and 4-6 bow ashis, with a mix of light/yari cav and flavour-of-the-month foot samurai.

The Date AI fields some rather terrifying stacks of half katana and half bow samurai.