Unfortunately I still haven't seen Ancestral Guardian at the table yet. Does Spirit Shield help enough to matter, or does it just leave your party with a few more unused Hit Dice at the end of the day?
On the Spirit Shield: I like this very much as you can decide on which party member you are going to prevent damage.
Sure, in ideal situations, this varies little as damage is soaked by the tanky ones. But any damaged saved from the party member that doesn't have a healthy pool of HP left, means that they can stay in the fight, without needing some in combat healing (through potion or spell). Which has it's tactical benefits and for my build, it utilises the Reaction, which doesn't see much use until now.
It gives some more tactical flexibility.
FYI: I'm currently playing level 7 Barbarian. Of course you don't know how things would have been if Spirit shield didn't prevent as much damage, yet it feels good to be able to protect the more squishy ones.
This one I have to disagree. Frenzy barely exceeds
Zealot's standard damage, and if you need it early on then you're nearly useless for non-combat encounters (skill checks) the rest of the day.
Well like the OP says in that thread: these are whiteroom comparisons of 21 rounds and have their average DPR printed. Which it doesn't take into account is the number of attacks which are made.
If both builds only target a big boss, than this is a sensible thing to compare. Yet there are things as multiple targets in combat, builds take feats, which allow to benefit more from certain scenario's.
The fact that the damage of a Berserker is spread over more attacks, is valuable as you can direct the damage to where it is needed. Because over kill, isn't taken into account to average DPR, this misrepresents things.
Nonetheless, the exhaustion limitation on the Frenzy Rage is poorly designed, that is true. It would have been better that it had a hard limit per long rest. Like 1 until level 9, 2 charges from 10-15 and 3 from level 16, or something along those lines. Or you could imagine, that they could use one more Frenzy than listed, and that one would cause Exhaustion.
But most of the time Berseker is more than fine, if you use it wisely. It's just not that shiny as it puts more Barbarian into your Barbarian so it seems bland at the surface, yet a Barbarian is something to be feared, so a more angry Barbarian,....