Biggest problem: You can't spam enough!!! Fearless Cleave is good, but once you're in the thick of fighting with monsters that don't try to run away you really shouldn't be spamming it. You SHOULD be spamming Death Dance! What is the point of this huge stamina bar if I can't empty it when surrounded by enemies? Also, Executioner needs changed because it makes healing from Bloodbath a little too reliable for Berserkers.
Death Dance
You spin me round round, like a record baby round round round round for 80%-130% (was 220%) base damage. Shreds (5 x skill) Armor on hit. Cooldown 10. Cooldown lowers by 2 for every enemy you hit with Death Dance. Stamina cost (x) (I don't remember the base, can be tweaked if needed).
Damage nerf needed on this with or without the cooldown reduction aspect, but I think this really needs to have a lower CD if you're using it properly (in the middle of a big group of monsters). Bleed removed, replaced with something more useful for non-Berserkers

Execution
Double your critical hit chance (not guaranteed). Do an extra x% dmg for every 1% missing enemy hp. Cooldown 10. Cooldown is instantly reset if you deal a killing blow with Execution, and half the Stamina cost is refunded as you savor the death of your foe. Stamina cost (x) (I don't remember the base, can be tweaked if needed).
Again, there needs to be a reward for using Execution properly, as well as giving encouragement to put more than 1 point in the skill. In this example pumping Execution massively improves the odds it will be instantly reset and available to use again when you use it vs. wounded enemies.
Net Benefit
So what do we gain from these further changes? Better combat options!!! Right now I'm about level 25 and every time there is a big group fight I pop my Death Dance and kill a few guys, pop my Execution / Stunning blow to kill some more, then wait for cooldowns while mashing direction keys to finish the job. This isn't fun or interesting. I'm sitting around with lots of Stamina locked away behind cooldowns I can't use. Especially when you have Executioner guaranteeing you never lose your Bloodbath stacks, keeping your Stamina regen at +5 for the duration of the fight.
With these changes you would be able to decide to burn all your Stamina while using your abilities appropriately for the situation, and have more interesting decisions to make during combat than which guy to bump attack while waiting for your CDs to end. 2H Assault would then be an even more dynamic category which rewards good decision making and resource management with better control over the flow of combat and your own ability cooldowns. As well, it is easy to justify maxing out skills that you can use more than once per combat, so competition for your class points increases.
Other Concerns
There are other Berserker skills that are a little wonky in how they scale at the moment and I'm keeping an eye on them. Bloody Butcher for example does not scale well past 2 points, nor does Berserker Rage itself. You want to max Rage for the Stun and Pin resist of course, but the returns just don't feel meaty past 3 points. Maybe they don't need to, idk, but I'm watching. Shield Defense and Archery Training are going to be removed from Berserker entirely soon since they don't serve any purpose (you don't have a 1H offense tree to use with a shield...), and even DarkGod acted surprised when I mentioned they still have the Archery training category, so I assume he doesn't think they need to keep it. I'm almost 100% sure nobody here used either one

As far as Superiority and Warcries I need to experiment with those and figure out what needs done with them. I did not touch them in the Berserker rework on purpose. I still think Bloodthirst as a tree needs to be available by default because it would be very silly to play a Berserker without it, but there is the interesting dynamic of level pre-reqs and "should Unstoppable be available before level 10?". I kind of feel like 22 is a good level to get Unstoppable at, so I'm not sure what to do about this situation. Perhaps there needs to be a split for Bloodthirst into a "basic" version that has Bloodbath and the advanced category that includes Unstoppable. It would be easy to merge some of Combat Techniques / Superiority / Warcries into this new split. Really I just don't want new Berserkers locked out of Mortal Terror and Bloodbath behind category points, because those are so key to playing the class. Unstoppable is as well, sure, but it is powerful enough to justify the category cost, and I would like to actually try to make a category to compete with it based on Constitution, giving players more build choices.