Here is my homebrew subclass for the 2019 UA Artificer class:
Armorer
Tools of the Trade
By the time you adopt this specialty at 3rd level, you’re deeply familiar with employing its tools.
Proficiencies: You gain proficiency with smith's tools and cobbler's tools. You also gain a set of alchemist’s supplies and an herbalism kit for free—the result of tinkering you’ve done as you’ve prepared for this specialization.
Crafting: If you craft a magic item in the armor category, it takes you a quarter of the normal time, and it costs you half as much of the usual gold.
Subclass Spells
Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Alchemist Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.
3rd level: Shield of Faith, Armor of Agathys
5th level: Warding Bond, Barkskin
9th level: Tiny Hut, Crusader's Mantle
13th level: Stoneskin, Fire Shield
17th level: Antilife Shell, Circle of PowerHeavily Armored
After a long rest, you can touch one set of heavy armor and imbue it with magic over the course of 10 minutes. This magic lasts until you take another long rest. You are proficient in heavy armor that has been imbued in this way. Only you can wear the armor that has been imbued in this way by you.
You have a number of Armorer Points (AP) equal to your Artificer level. When you imbue the armor with magic, you can spend AP to give the armor enhancements listed below, these enhancements cease to operate after the armor's magic wears off. AP is also used for features you will gain at higher levels. You regain any expended Armorer Points when you take a long rest.
Projectile Protection
Cost: 5 AP
You have resistance to piercing damage from ranged weapon attacks while wearing this armor.Flight
Cost: 18 AP
You gain a flying speed of 30 feet while wearing this armor.Mobility
Cost: 3 AP
You ignore difficult terrain while wearing this armor.Speed
Cost: 2-20 AP
Your walking speed increases by 5 feet for every 2 AP you spend on this Enhancement.Aqua Affinity
Cost: 2 AP
You gain a swimming speed equal to your walking speed.Flamethrower
Cost: 17 AP
You can cast Firebolt as a bonus action while wearing this armor.Electrified
Cost: 2 AP
Whenever a creature starts their turn grappling you or being grappled by you, they take 1d4 lightning damage.Night Vision
Cost: 4 AP
You gain darkvision out to a range of 30 feet. You can't discern color in darkness, only shades of gray.Sonar
Cost: 8 AP
While underwater, you have blindsight out to a range of 120 feet.Precise Targeting
Cost: 3 AP
You gain a +1 bonus to ranged weapon attack rolls.Redirect Energy
Cost: 7 AP
When you take lightning, force, or radiant damage, you can use your reaction to force all other creatures within 30 feet of you to make a Dexterity saving throw; they take 2d10 thunder damage on a failed save, or half as much on a success.Respiration
Cost: 3 AP
While you are wearing this armor, you can breathe underwater.Tin Foil
Cost: 12 AP
While you are wearing this armor, your mind cannot be dominated, charmed, or read by a spell of 5th level or lower.Lantern
Cost: 2 AP
You shed bright light in a 30-foot radius and dim light for an additional 60 feet while wearing this armor.Strong
Cost: 3 AP
Your carrying capacity is tripled when wearing this armor.Scintillating Blade Cost: 9 AP
When you do slashing or piercing damage to a creature or object with a melee weapon, they take an additional 1d4 damage if they are a creature, or 8d4 damage if they are an object.Master of Armor
When you reach 6th level in this class, you can spend 10 AP to increase your AC by 3 for the next hour. Once you use this feature, you cannot use it again until you complete a long rest.
Supreme Master of Armor
At level 14, you gain proficiency in martial weapons. Whenever you take damage, you can spend AP to reduce the damage you take by 1d6 per AP spent.
I'm hoping to make a versatile tank subclass.
Is this homebrew Armorer Artificer subclass balanced compared to the 2019 UA Artificer subclasses?