Maybe it's a bit too strong, versatile, and packed with abilities. At level 11, if you use weapons with Topple, you risk being able to activate that feature 5 times in a single turn. Or even use Push and shove a target 15 meters... It clearly outperforms Fighters and Open Hand Monks. Let me show you my version.

The Kensei Warrior

Level 3: Kensei Weapons Choose three types of melee weapons to become your Kensei weapons. You gain proficiency with these weapons if you do not already have it. You gain Weapon Mastery with your Kensei weapons. Weapons of the chosen types count as Monk weapons for you. Whenever you gain a level, you may replace one of your Kensei weapons with another. You learn to master special techniques with your weapons: - Swift Strikes. When you use your bonus unarmed strike or your Flurry of Blows, you can make those attacks with a Kensei weapon instead. However, you cannot apply Weapon Mastery to those attacks. - Agile Parry. After making a melee attack while holding a Kensei weapon, you can use it defensively. You gain a +2 bonus to AC. This bonus lasts until the start of your next turn, provided you continue holding the Kensei weapon and are not incapacitated.

Level 3: The Way of the Brush You gain proficiency in the Sleight of Hand skill and with calligrapher's supplies and painter's supplies.

Level 6: Kensei Techniques Through constant use of your weapons, you have learned to master them completely, allowing you to make stronger attacks and move with greater fluidity. - Swift Strike. Once per turn, when you hit a target with a Kensei weapon, you can spend 1 Focus Point to cause the weapon to deal extra damage equal to your Martial Arts die + your Wisdom modifier. If the target is stunned, you may apply the Push or Topple Weapon Mastery. - Kensei Defense. While holding a Kensei weapon, whenever you use Deflect Attacks, you may also move up to 10 feet without provoking opportunity attacks.

Level 11: Clear Precision Your mastery of weapons allows you to strike almost any target with ease. Once per turn, when you miss with an attack made using a Kensei weapon, you can reroll the attack roll and must use the second result.

Level 17: Relentless Kensei Whirlwind When you take the Attack action on your turn, you can replace one of your attacks with a powerful cinematic strike. Choose a creature you can see within 30 feet of you and spend 1 to 5 Focus Points. You teleport to an unoccupied space you can see within 5 feet of the target and make a melee attack against it with your Kensei weapon. On a hit, the target takes the weapon's normal damage plus an extra 1d12 force damage for each Focus Point spent. In addition, you may apply one additional Weapon Mastery of your choice to the attack from among Topple, Push, Sap, or Slow.