I've noticed that many see the Samurai Fighter as underpowered, so I reworked it! Please tell me what you think!

Samurai

Level 3: Bonus Proficiencies

You learn a new language and gain Proficiency with Calligrapher's or Painter’s Supplies, in addition to Proficiency with two of the following skills of your choice: History, Insight, or Persuasion.

Level 3: Fighting Spirit

Your intensity in battle can shield you and help you strike true. As a Bonus Action on your turn, you can give yourself Advantage on all attack rolls until the end of your turn. When you do so, you also gain a number of Temporary Hit Points equal to your Fighter level.

You can use this feature a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a short or long rest.

7th Level: Elegant Courtier

Your discipline and attention to detail allow you to excel in social situations.
You can choose to use Wisdom in place of Intelligence or Charisma when you make a History or Persuasion check.

Your self control also causes you to gain Proficiency in Wisdom saving throws.

10th Level: Tireless Spirit

When you roll Initiative, you regain a use of Fighting Spirit. if you are not missing any uses of Fighting Spirit, you gain Temporary Hit Points  equal to your Fighter level.

15th Level: Rapid Strikes

You learn to trade accuracy for swift strikes. Once per Attack action, when you make an attack roll with Advantage, you can choose to forgo the Advantage and instead make two attacks. These attacks are made without advantage, as normal.

18th Level: Strength Before Death

Your fighting spirit can delay the grasp of death. If you take damage that reduces you to 0 Hit Points but doesn't kill you outright, you choose to instead be reduced to 1 Hit Point and immediately take an extra turn, interrupting the current turn. During this extra turn, there is no limit to how many times you can use your Rapid Strikes feature, and all attacks made against you have disadvantage. At the end of this extra turn, you are reduced to 0 Hit Points and begin to make death saving throws as normal.

Once you use this feature, you can’t use it again until you finish a long rest.

Sidenote, please do not be rude or aggressive with your comments. Thank you and have a wonderful day!

The capstone on the subclass looks like it works with the whole build so well. You could dump all of your damage right before fall through fighting spirit into rapid strikes to double your total attacks. I do think that the strength of the subclass is more dependent on the DM than most subclasses, However, i have no idea how you could fix that.

Thanks, I was worried it would be too strong, but I'm glad someone else doesn't see it that way.

Edit: Also, Rapid Strikes works with Haste. Neat!

The main DM issue is that because long combats invalidate the level 10 and fast hard combats invalidate the temp HP of 3rd. With a balanced DM I feel like this is above average but not as much as some official subclasses and at worst one or two low level feats lose a lot of their meaning. Plus a mainly combat class having good RP is interesting it just makes the combat part a bit less powerful.