Path of Blood Frenzy

Exhaustion is and has been far too costly for Berserker Barbarians. It's a shame that such a good and popular archetype falls flat under official implementation. Here's my stab at it, it'll need to be tuned down I bet.

Blood Frenzy

While raging, you can choose to enter a Blood Frenzy when you deal damage to another creature. At that time, make a Blood Sacrifice, rolling one of your Hit Dice to gain 1d12 + CON temporary hit points. As long as you have temporary hit points from the Blood Sacrifice special action, and are raging, you are in a Blood Frenzy, in which the following effects apply:

• Any time you deal damage to a creature other than yourself, you can make another Blood Sacrifice to gain additional temporary hp.
• Any temp hp you gain from additional Sacrifices is added to your previous sum, rather than replacing it.
• If you have made a Sacrifice on your turn, you can make 1 unarmed strike against a single target as a bonus action, increasing by 1 additional strike at each 6th, 10th, and 14th levels.
• If your temporary hp falls to 0, or is replaced by another source of temporary hp during your rage, your rage ends.

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When your rage ends, you lose all your remaining temporary hit points as the rage subsides, and subsequently lose 3d4 hit points for each Blood Sacrifice made during your rage. Then make a (DC 10 + Sacrifices) CON save, on a failure, you are Deafened and Blinded until the end of your next turn, or upon success, until the start of your next turn. 

Restless Heart

When you would fail a death saving throw, it automatically becomes a success, and you gain one point of exhaustion.

Sanguine Charge

Beginning at 6th level, when you kill a creature within your reach, you can use your reaction to dash 15 ft in a straight line towards another creature of your choice, ignoring Difficult Terrain and occupied spaces.
If they can see or hear you, any creature in your path must make a WIS saving throw (DC 8 + proficiency bonus + STR) or be Frightened by you until the start of its next turn.
You can do this a number of times equal to your proficiency bonus per long rest.

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Additionally, if you are in Blood Frenzy, you can make a Sacrifice to empower your charge, dealing Necrotic Damage equal to your WIS modifier to any creatures that fail their save. Then roll 1d4 for each creature you have frightened and gain temporary hit points equal to the total, instead of the normal amount you would get from a Sacrifice.

Thundering Shout

Beginning at 10th level, as an action, you can let out a Thunderous war cry, making you and all creatures within 15ft of you able to hear you Deafened for 1 minute.
You all must then make a CON save (DC 8 + proficiency bonus + WIS) or take 4d8 + WIS Thunder Damage, or half as much on a success. 
Creatures who fail the save by more than 10 - your Wisdom modifier are Stunned until the end of their next turn. 

You can make a Thundering Shout twice per day, regaining both charges at dawn each morning. 

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Additionally, if you are in a Blood Frenzy, you instead use Thundering Shout by Sacrificing 3 hit dice, when you do so, you have disadvantage on the save. You can only do so if you are already able to sacrifice a minimum of 3 hit dice per turn.
If you stunned any creatures, roll 2d4 for stunned each creature and gain temporary hp equal to the total, instead of the normal value you would gain from the dice Sacrificed in this way. 

Vampiric Hunger

Whenever you have less than a fifth of your hit dice, rounded down, once a turn, you can make a melee weapon attack deal an additional 1d8 + WIS Necrotic Damage.

Additionally, when you roll an 8 with the additional die, one of your hit die is restored.