This subclass has received significant changes
You can add your full Dexterity modifier to your Mage Armor, and you Master one melee weapon with the finesse property. You count as proficient with that weapon and gain either the Mastered weapon’s Signature Mastery or the “Specialist” Mastery Property. Whenever you finish a Long Rest, you can practice weapon drills and change the kind of weapon you choose. While holding a one-handed Mastered weapon you can use it as a Spellcasting focus for your Wizard spells.
You also gain proficiency in the Performance skill or any one skill of your choice if you already have it.
Mastery Ability
Dexterity is your Mastery ability for your weapon masteries, meaning you use your Mastery ability modifier when setting the DC for a any masteries that impose a saving throw.
Mastery Save DC = 8 + your Proficiency Bonus + your Mastery modifier
You can invoke an elven magic called the Bladesong, provided that you aren’t wearing medium or heavy armor or using a shield. It graces you with supernatural speed, agility, and focus.
You can start the Bladesong as a bonus action or as part of the bonus action used to cast a spell. The Bladesong lasts for 1 minute but ends early if you are incapacitated, if you don medium or heavy armor or a shield, if you attack with a weapon without the finesse property, if you start a new Bladesong, or if you end the Bladesong with a Bonus Action.
While your Bladesong is active, you gain the following properties:
You gain a bonus to your AC equal to your Spellcasting modifier (minimum of +1).
Your walking speed increases by 10 feet.
You have advantage on Dexterity (Acrobatics) checks.
You gain a bonus to any Constitution saving throw you make to maintain your concentration on a spell. The bonus equals your Spellcasting modifier (minimum of +1).
You cannot make Power Attacks
You can only cast spells of 1st level or lower
When you reach higher levels, the maximum level of spell you can cast while in Bladesong increases. You can cast up to 2nd level spells when you reach 5th level, 3rd level spells at 9th level, 4th level spells at 13th level, and 5th level spells at 17th level.
Once per turn on your turn when you take any action but casting a spell of 1st level or higher, you may take a second action. This action may be any action except for casting a spell. In addition, you can now make Power Attacks while in your Bladesong.
Your mastered weapon gains an additional Mastery Property. The Property can be the “Specialist” property or one property from that weapon’s available Mastery Properties. Whenever you finish a Long Rest, you can practice weapon drills and change the additional Mastery Property you choose.
You can direct your magic to absorb damage while your Bladesong is active. When you take damage, you can use your reaction to expend one spell slot and reduce that damage to you by an amount equal to five times the spell slot’s level.
You can add your Spellcasting modifier (minimum of +1) to the damage of your melee weapon attacks while your Bladesong is active.