Barbarian Subclasses, Revised
A handful of Barbarian subclasses range from either completely underpowered to just sub-par. The Battlerager, Berserker, and Storm Herald subclasses are all lacking compared to the other Barbarian subclasses, so I've attempted to update them to be more on par.
Path of the Battlerager
Battlerager Armor
When you choose this path at 3rd level, you gain the ability to use spiked armor as a weapon.
While you are wearing spiked armor and are raging, you can use a bonus action to make one melee weapon attack with your armor spikes against a target within 5 feet of you. If the attack hits, the spikes deal 1d8 piercing damage. You use your Strength modifier for the attack and damage rolls, and are proficient with it.
Additionally, when you use the Attack action to grapple a creature, the target takes piercing damage equal to half your barbarian level, (rounded up) if your grapple check succeeds, and at the start of each of its turns that it remains grappled by you.
Battlerager Charge
At 6th level, you can take the Dash action as a bonus action while you are raging. Additionally, the first time you hit a creature with an attack after taking the Dash action, the target takes additional damage equal to your Proficiecny Bonus.
Reckless Abandon
Beginning at 10th level, when you use Reckless Attack while raging, you also gain temporary hit points equal to your level in this class. They vanish if any of them are left when your rage ends.
Spiked Retribution
Starting at 14th level, when a creature within 5 feet of you hits you with a melee attack, the attacker takes piercing damage equal to twice your rage damage if you are raging, aren't incapacitated, and are wearing spiked armor.
Path of the Berserker
Frenzy
Starting when you choose this path at 3rd level, when you take the Attack action on the same turn that you enter rage, you can make an extra attack as part of the same action.
Additionally, when you enter rage you can go into a frenzy. If you do so, for the duration of your frenzied rage, your rage damage bonus is doubled, and on subsequent turns when you take the Attack action, you can make an additional attack as part of that Attack action. Once your frenzied rage ends, you must make a DC10 Constitution saving throw or suffer one level of exhaustion. Each time you use this feature after the first, the DC increases by 5. When you finish a long rest the DC resets to 10.
Mindless Rage
Beginning at 6th level, you have advantage on saving throws against being charmed or frightened, and you can't be charmed or frightened while raging. If you are charmed or frightened when you enter your rage, the effect is suspended for the duration of the rage. Additionally, while raging, you have resistance to psychic damage.
Intimidating Presence
At 10th level, you gain proficiency in the Intimidation skill, if you don't already have it. You gain a bonus to Intimdation checks equal to your Strength modifier. As a bonus action on your turns, you can make an Charisma (Intimidation) check against a creature that can see or hear you, contested by the target's Wisdom (Insight). If the target fails, they become frightened of you until the end of your next turn. If the creature succeeds, it is immune to this effect for 24 hours.
Additionally, you have advantage on melee attacks made against creatures that are frightened of you, and frightened creatures within your reach provoke opportunity attacks even if they took the Disengage action.
Retaliation
At 14th level, when you take damage from a creature within your reach, you can use your reaction to make a melee weapon attack against that creature. If the attack hits, you deal extra damage equal to your Barbarian level.
Path of the Storm Herald
Storm Aura
When you select this path at 3rd level, you emanate a stormy, magical aura while you rage. The aura extends 10 feet from you in every direction, but not through total cover. The range of your aura increases to 15 feet at 6th level, 20 feet at 10th level, and 30 feet at 14th level.
Your aura has an effect that activates when you enter your rage, and you can activate the effect again on each of your turns as a bonus action. Choose desert, sea, or tundra. Your aura's effect depends on that chosen environment, as detailed below. You can change your environment choice whenever you gain a level in this class.
If your aura's effects require a saving throw, the DC equals 8 + your proficiency bonus + your Constitution modifier.
Desert. When this effect is activated, other creatures of your choice in your aura take 1d4+2 fire damage each. The damage increases when you reach certain levels in this class, increasing to 1d4+3 at 5th level, 1d4+4 at 10th level, 1d4+5 at 15th level, and 1d6+6 at 20th level.
Sea. When this effect is activated, you can choose one other creature you can see in your aura. The target must make a Dexterity saving throw. The target takes 1d6 lightning damage on a failed save, or half as much damage on a successful one. The damage increases when you reach certain levels in this class, increasing to 2d6 at 5th level, 3d6 at 10th level, 4d6 at 15th level, and 5d6 at 20th level.
Tundra. When this effect is activated, each creature of your choice in your aura gains 1d4+2 temporary hit points, as icy spirits inure it to suffering. The temporary hit points increase when you reach certain levels in this class, increasing to 1d4+3 at 5th level, 1d4+4 at 10th level, 1d4+5 at 15th level, and 1d6+6 at 20th level.
Storm Soul
At 6th level, the storm grants you benefits even when your aura isn't active. The benefits are based on the environment you chose for your Storm Aura.
Desert. You gain resistance to fire damage, and you don’t suffer the effects of extreme heat, as described in the Dungeon Master's Guide. Moreover, as an action, you can touch a flammable object that isn't being worn or carried by anyone else and set it on fire.
Sea. You gain resistance to lightning damage, and you can breathe underwater. You also gain a swimming speed equal to your walking speed.
Tundra. You gain resistance to cold damage, and you don’t suffer the effects of extreme cold, as described in the Dungeon Master's Guide. Moreover, as an action, you can touch water and turn a 5-foot cube of it into ice, which melts after 1 minute. This action fails if a creature is in the cube.
Shielding Storm
At 10th level, you learn to use your mastery of the storm to protect others. Each creature of your choice has the damage resistance you gained from the Storm Soul feature while the creature is in your Storm Aura.
Raging Storm
At 14th level, the power of the storm you channel grows mightier, lashing out at your foes. The effect is based on the environment you chose for your Storm Aura.
Desert. Immediately after a creature in your aura hits you with an attack, you can use your reaction to force that creature to make a Dexterity saving throw. On a failed save, the creature takes fire damage equal to your Barbarian level, or damage equal to half your Barbarian level (rounded down) on a success.
Sea. Once per turn, when you hit a creature in your aura with an attack, you can force that creature to make a Strength saving throw. On a failed save, the creature is knocked prone, as if struck by a wave. On a successful save, the creature is instead pushed up to 10 feet away from you.
Tundra. Whenever the effect of your Storm Aura is activated, you can choose one creature you can see in the aura. That creature must succeed on a Strength saving throw, or its speed is reduced to 0 until the start of your next turn, as magical frost covers it. On a successful save the creatures movement speed is only reduced by half.