It really depends on makeup. If you have warriors to do it, sure, they're probably the best choice. But not all guilds have warriors, some will have a warrior tank, some DPS warriors, others won't have any.

Obviously if I'm in a raid I'm a DPS warrior in it, and so I almost always handle the interrupts. I've got two fear breaks (Berserker Rage/ Every Man) and so I can sit in front of her, babysit my cooldowns and pummel pretty much every single Sentinel Blast. But if you don't have a war, there's always the ol' Fear Ward/Rogue rotation.

If you have interrupts to use, and the fight has no enrage timer, what reason is there to not use them?

As you say - you absolutely 100% cannot cloak out of her fear, and you cannot cloak in advance of the fear.

I tested this for about 4 hours of attempts several weeks ago.

If you spec into throwing specialization ( as I do for ulduar) losing only one point in lethality doesn't hurt your dps too much. you have an aoe interrupt that is very effective on the razorscale fight as well as on Auriaya, as you don't have to be in melee range to interrupt her. just thought I'd put my 2 cents in on this one

I have noticed some strange bugs with Throwing Specialization lately. We tried having a designated interrupter (me) last night, and before we had the Killing Spree/Fear Ward rotation set up I got hit with a fear with a few combo points built on Auriaya. I'm specced 2/2 into Throwing Specialization, so I hit Deadly Throw. It damaged her but did not interrupt the spell, and I had to run over and kick her in the kneecaps.

On several guild runs, I have been asked to interupt on that fight. Since I don't pvp much and I haven't used mutilate in a while, I went ahead and created a dual spec that had 2/2 in throwing spec. Now when I am needed to interupt on that fight, I just switch over to my dual spec and use FOK for the interupts.

I also went ahead and grabbed the FOK glyph for that secondary spec and use it in the arena on Thorim. I had 124 interupts last week on Thorim.