This is totally dependend on encounter design. For example at Brutallus it will be godlike, you have barkskin ready for every Stomp. If a boss enrages he often makes 10x the damage as normal so shield wall is nothing which helps there really.

These are now categorized seperately (not sure if you made a typo or not).

Berserk = Instant raid wipe (400-1000% dmg)
Enrage = Usually low % based, or sometimes "timed" with someway to clear it (see Grand Widow)
Frenzy = Dispellable "Enrage" via Tranq Shot, etc.

All the other tanks shieldwall abilities have at least 50% damage reduction (warriors get 60%) - we only get 20%. While this is fine for long term damage reduction i see a problem with encounter specific issues.

Any encounter with a short and brutal enrage/berserk which the tank has to live through (or at least live as long as possible) will heavily favor any other tank class over us.

So in order to maintain their "every tank can tank every boss" mentality they cannot design encounters with aforementioned mechanic or they have to adjust barkskin accordingly.

And again, giving too much power to Barkskin greatly affects Resto PvP balance unless it's talented in deep feral tree.

We may end up with encounters that favor the Druid's much smaller cooldown and others that favor the higher mitigation of Shield Wall. I don't necessarily mind that Barkskin is only 20% if that shorter cooldown can be put to good use.

Barkskin also has good potential in pvp. If you're in a longer arena fight, the damage reduction on a regular basis would certainly come in handy.

This. SWP is pretty much designed without the use of Shield Wall from what I can tell so if they keep it like that, then we could use SWP as an example on how good Barkskin could be. Barkskin during a Sathrovarr stun will be nice, during every Stomp on Brutallus, during every (or every second, depending on your luck) Corrosion on Felmyst. I don't really know if you even need it at Twins but you could do it just before a Confounding Blow I guess. On M'uru you could use it once per wave of adds. The only Boss I'd say SW is better would be Kalec if you took your time getting him past 10% so he stacked up too many Enrage stacks but that's about.

About Bear AoE tanking: Anyone else want to see Hurricane in Bear form? You know you want to. <_<
I always thought it would be nice if they gave Druids the old Hurrican back which you could fire and forget instead of the one they have now that breaks when you stop the channel.

You're forgetting situations where you dip low and you suddenly need an OHSNAP button to recover. Even if you're fighting bosses that don't enrage, there's always times where you need a shield wall button, and Barkskin just isn't going to cut it.

Even with the GCD, it'd still be effective at saving you from certain death.

It'd be like a higher damage consecrate with a longer cooldown. It would fit rather nicely with how they've been altering abilities to pass them around while maintaining core tanking functionality with subtle (or not so subtle) differences.

There is a trinket in wowhead database (cannot link for some reason) like this:

Defender's Code
Binds when picked up
Unique
Trinket
850 Armor
Requires Level 80
Use: Increases parry dodge by 455 for 20 sec. (2 Min Cooldown)


Looks like a really awesome upgrade from BoT. Also it has the parry dodge thing mentioned earlier.

Wow, the armor on that thing is ridiculous.

Ridiculously sexy.

Probably going to be using both BoT and this new trinket, unless there's another hot trinket out there.