A question of quality over quantity. Often it is better to master what you know instead of learning more.

 

Level 3: Expanded Surge

You can now use your Action Surge to grant an additional action or bonus action on your turn.

Level 7: Quick Reflexes

You can now use your Action Surge to grant an additional reaction this round.

Level 10: Necessary Resilience

If you are out of uses of Second Wind, you can expend a use of Indomitable to use it instead. If you are out of uses of Indomitable, you can expend a use of Second Wind to use it instead.

Level 15: Advanced Mastery

Your Weapon Mastery gain additional effects depending on which is use. 

• Cleave: You can apply the Cleave to an Attack made with a bonus action without it interfering with applying Cleave to an Attack made with your action (or vias versa).
• Graze: The damage from Graze now increases by 2 when dealt to a creature who you have already damage with Graze this action.
• Nick: You can apply the Nick to an Attack made with a reaction without it interfering with applying Nick to an Attack made with your action (or vias versa).
• Slow: Any Attacks made while under the effects of Slow after using all their movement is made at Disadvantage.
• Topple: Any creature that fails their save against your Topple takes Bludgeoning damage = 2 time their size category (ex. Tiny=2, Medium=6, Giant=24...)
• Sap: If the Disadvantaged Attack still hits, its damage is reduced by the ability modifier you used to make the Sap Attack roll.
• Push: the Creature that is Pushed has Disadvantage on it's next Attack role if its against an ally within 5ft of you.
• Vex: You have a temporary +1 bonus to your AC = to the number of times the attacking creature has been hit with your Vexing Attack since the end of your last turn.

Level 18: Decisive Action

If you are out of uses of Action Surge, you can expend a use of either Second Wind & Indomitable to use it instead or vias versa.