I agree with this.
While the dragon's animation in the trailer is no different than bosses today that doesn't mean that I like the behavior in 1.0 either. I think having the monster react to weapons skills/percent damage/critical hits only would be much more effective.
Having a ferocious beast seemingly unphased by your normal attack makes that beast much more intimidating, giving the fight a greater sense of challenge. It also opens up psychological avenues as well. What happens when that previously unflinching ferocious beast reacts in pain to your critical weapon skill. That feels like a much greater accomplishment than if it were just standard behavior, and I think that's the core of the problem.
Upon the first watch I didn't really notice anything wrong with the fight. When I fight Ifrit I don't really notice it either. If it were more of a rare occurrence then maybe I would and it would also provide me with a positive feedback loop.
So in my opinion, while it's not a problem per se, I think the feel of battle would greatly benefit from "adding some weight" to bosses a little more.
