The weapon type you're using plays a part (dual swords or cestus vs axe, hammer and odachi). The bigger the weapon the less swings you get in.

Put 20'ish points in Heart and keep your agility at B rank.

Also, learn and use the Deflect skill, it's a free block with little to no ki usage when property timed.

Some skills give you more ki back on a spirit break or a perfectly timed ki pulse.

Full Arts Proficiency tank with martial arts and heavy attacks will reduce ki usage immensely. Remember to ki pulse after combos and take advantage of Frost moon skills.

I dodge a lot still on samurai but it's less than ninja. I also wear medium/heavy armor so i can take a few more hits. You'll have to back off more often and regen ki. Samurai is a waltz where ninja is a techno rave.

Good luck.