You are correct bok, but I would point out that "bursts" of damage are usually not 1 ability but several in a very small timeframe. Auto+big ability+lesser ability in 1-2 seconds is what drops most tanks.
If you parry any of these, you are more likely to survive long enough for a heal so goes the theory.
I still think this thread has not proven either is better, and I think I am going to go with a middle of the road approach. ~500ish parry, some good crit and det, with just tiny bit of ss since it will probably be on some piece of otherwise great gear.