Tired of seeing this argument as well because its quite simply NOT like this in practice.
A Reprisal would be the icing on the cake, other CDs should be up. A Reprisal by itself is simply not ever going to save you.
Also again, sure its RNG, but if you don't parry once in 20 seconds with a 50-60% chance to do so, LOL, I'm sorry but that's just not a common enough problem to warrant a mechanical change.
I can see this argument working if I was trying to say that you should use Dark Dance in the hopes of parrying one specific hit, because as PLDs in T13 learned with Bulwark, you can and will get fucked over, but that's not what we're talking about here, which leads me to my next point.
Because what else would you use a parry rate increase for? Mitigating auto-attack damage before/after TBs? oh wait...
The way this works is actually very good design, IMO, because it helps shave off the amount of damage you take from autos leading up to a TB, thus requiring less heals to top you off (potentially), and then get a present for it (Reprisal).
In A2S, both were a big part of my CD rotation. While things like SS and SW were on CD I would pop Dark Dance and then put Reprisal on the Doll I was not focusing and therefore not facing and therefore unable to parry its attacks.
Here's some math:
If a boss auto attacks you every 3 seconds and you have Dark Dance up, you have around a 0.083 chance, assuming NO investment in your parry stat, to NOT get a single Reprisal proc inside that 20 seconds. If you land on the pear-shaped side of such odds, I'm really sorry, but you're probably just unlucky. I reiterate, I've never been left wanting for a proc in any situation in savage thus far in which my life depended on it. =/
I feel that the job plays extremely well, and I was not a "paper tank" as so many people warned me that DRK would be in A2S (I'm able to spend almost as much time out of tank stance in there as my WAR OT, and he only gets more time out of it b/c we kill his adds first, naturally). Does it have strengths and weaknesses? Absolutely. But so does every job in the game other than WAR (the whole point of this thread). Do its strengths/weaknesses break it? Nah.