Smiles at all the wonderful discussion going on.
Soooo, there have been some great points on both sides of this argument. Before I jump back in, I would like to describe myself somewhat. My motivation is basically this. If someone says X sucks and Y is way better, but in my mind I see them as both good choices depending on the situation and preference, I tend to defend X.
I would like to give props to @
RulesJD to pointing out that the lvl 3 Bear totem ability will lead to some dps increase, I hadn't really accounted for that. @
DaveDash also pointed out that that GWM and Frenzy is probably the best burst damage Barbarian combos and also showed us from personal account just how beneficial Mindless Rage can be. And earlier even though I did commend on it earlier @
The_Furious_Puffin correctly noted that in the right party the lvl 3 Wolf Totem ability is badass, and reminded us that Retaliation is a very long way off at lvl 14.
Where does this leave us, and am I even the right person to try and put my biases aside and looks at both sides of the issue (and is it really possible to put your biases aside)? I will try anyways. The question could be asked which is better? After this is done, then that side could argue that since Y (Totem Warrior) is better than X (Berserker), then X needs a buff to compensate. But something will always be considered better or best, so instead of saying in general Y is better than X, I would rather look at party makeup and show which is the better option in each situation. My thesis is that in some parties, the Totem Warrior will be more effective (bear or wolf at lvl 3), while in other parties the Berserker will be more effective, therefore Y is not better than X all the time.
First, there is a very important spell that really decides the value of Mindless Rage. Calm Emotions is on both the Bard's and Cleric's spell list, if your party has a Bard or Cleric that knows how good this spell is and prepares it and saves it for when it is needed, Mindless Rage is less important. It will immediately end any charm or frightened condition, (granted the Barbarian may still lose his attack depending on the order of initiative).
Second, in a melee heavy party (pretty much any party with 1 or 2 other melee characters, preferably Fighter, Rogue, Monk, Ranger, Paladin or Barbarian). The Wolf Totem lvl 3 ability will most likely be your strongest choice.
Third, if your party has ways of granting advantage, Bless, and or Bardic Inspiration, then GWM will be the default feat of choice. (The only reason that this is relevant is that GWM has more synergy with Berserker than PM).
A few weeks ago I was helping a player in my campaign make a badass Barbarian. He actually wanted to be very tanky, so I naturally thought Totem Warrior Bear. But when we talked about Fear and Charm this lead in the direction of Berserker. It should also be noted that this Barbarian is the only melee character in the group. For example (and I know this is a horrible example), if the parties archer Fighter and the Barbarian fought, to win the archer Fighter would just Menacing Strike (caused the frightened condition) all day. A Totem Barbarian is really screwed in this example, while a Berserker (lvl 6 on up) is not.
So to recap, in any given situation Y will be better than X, in another one X is better than Y. Can we say which is more likely? Probably. But imo figuring out which is better in the given situation is more important.
Edited for my poor wordiness and typos and stuffs.