Disarm immunity and tanking.. oversight?

Ok, it clearly appears that the reason for changing the disarm immunity mechanics is to make it worth the trouble in PvP. Because there is no reason to disarm in PvP if everyone serious about PvP has immunity. That simply means the pros own the noobs even more. So fair enough about that change.

But seriously Blizzard. Did you consider the impact on Heroic tanking?
Ramparts, BF, Crypts and SH (not sure about the last one - and there might be more) All have mobs that disarm, and they are quite happy about spamming disarm even.
When you are tanking 2 of those mobs at the same time (not unlikely at all) you are pretty sure to be disarmed close to 90% of the time.

Warriors have TWO threat moves that works while disarmed, shield slam and shield bash. One has a 6 second cooldown and the other a 10 second cooldown. Thunderclap, and demo shout works too, but both have so low threat or long cooldowns that they are not worth mentioning.
And do not forget that rage generation is severely gimped while disarmed too. The warrior only gets the rage from taking damage.

Now, how exactly are we supposed to tank those instances when our threat is cut at least in half? (assuming the current disarm spam is the real frequency and 50% duration would actually cut the time disarmed down by 50%).

Right now I have a pair of steelgrip gauntlets that I slap on for tanking those instances. Yes, I make a choice to gimp some tank stats in order to avoid getting disarmed. That tactic will be worthless after patch 2.3, as the 50% reduction is not going to be enough when you have two mobs disarming you with independent cd timers. You will STILL get disarmed so much that your threat is gimped.

And how exactly is Blizzard going to justify that WARRIOR threat generation is affected by this, while druid and paladin threat generation is completely unaffected?

So Blizzard:
Either rethink the disarm immunity change.
Or simply remove the disarm ability from all mobs.