The concerns being raised here stem from concerns that many of us brought up during beta, only to have certain well-respected members of the community argue with. There are still a significant number of people arguing that bears are "fine". Well "fine" and "viable" don't equal good or desirable. Here are some of the issues as I see them:
The Bear as it has existed since patch 1.8 does not fit Blizzard's active mitigation model. Passive mitigation/avoidance was ALWAYS a bear thing since the days when Warriors were spamming shield block to avoid crushing blows and we were eating them with our high armor or dodging them completely with high dodge. Blizzard tried forcing active mitigation on us before to an extent by reducing our armor and giving us the original Savage Defense, which some of you will remember was a mediocre absorb mechanic riddled with issues. Eventually our armor was given back and SD changed from an absorb to a drastically increased chance to dodge, and while good bears were using SD, it was certainly not vital to our survival. Then we get to WoD and Blizz is pushing for tanks to be even more reliant on active mitigation. The obvious way to do this is by reducing your passive mitigation/avoidance to FORCE you to depend on those AM buttons. The problem is, out of all the tanks, bears still do not have a true active "mitigation" button.
Solution: Re-design Savage Defense to be an absorb again, effectively a "bear block". Scrap the current mastery, and tie it to SD the way it is for other tanks. Personally I'm not a fan of AM period (am I the only one who remembers when crushing blows were removed because Blizz acknowledged having to time shield block to line up with them wasn't fun?) but since it looks like it's here to stay, we need a reliable way to do it. Wouldn't mind having Might of Ursoc back either since we are now the only tank lacking a Last Stand-type ability. Give it a 3 min cd.
I also feel Pulverize should be baseline again (it was in Cata). Perhaps reduce our HP bonus and make Pulverize baseline. Like others have said, having a more moderate health pool and better overall survival is much more desirable in a raid setting than a huge health pool that is frequently spiking. And as was shown in this thread, healers aren't watching to see if you heal yourself when you spike, they're going to race to get you back up at the same time you're popping FR and that hurts everyone.
Then there's the matter of our AoE: No one can argue that Thrash was ridiculous the way it went live, but it was our ONLY aoe. There was no good reason for the removal of Swipe. Button bloat has never been an issue for Druids due to forms and Bears have always had one of the smallest toolkits of all the tanks.
Solution: Bring back Swipe, put a 15-30 sec cd on Thrash.
Our utility is still severely lacking, as it has since we lost the ability to play as bearcats (which you could argue was never really "tank utility" anyhow). There is no good reason for us to still not be able to brez in form without relying on DoC to proc. If a fat chicken can ride a mount, a bear can wiggle its toes and cast a rez. I wouldn't mind seeing something like Demo Roar come back honestly.
The idea that "Bears will get better with gear" is poor game design. No guild when given a choice wants to carry the tank that "gets better with gear" on progression fights and we should not feel compelled to gear out another tank class to avoid burdening our guilds until content is on farm.