Your post is dangerously close to whining/Blizzard should have done X instead of Y. We deal in the real (virtual) world here. This is the bonus, this is what it does, this is what I see as a problem with it, etc. If you have a suggestion to change it, visit the WoW forums. No one here cares.
Originally Posted by slourette
I disagree with this statement. If you don't know what to do with your freed GCD from the set bonus, then what will you do with your extra 4-5% haste from swapping your crit tier to haste pieces? On average, the set bonus will save you one GCD for every 7 rejuvs you cast. Assuming that rejuv is at between 50-80% of our GCD's, the set bonus is equivalent to a 7-11% haste buff, which can yield throughput beyond what is possible with just haste due to the cap. The set bonus is worth significantly more than the haste lost in order to achieve the set bonus, and it's a straight upgrade, not a trade off.
The strongest argument I see for not taking the set bonus is that it will save you one GCD every 7 rejuvs on average, which means you can be unlucky. However, I believe that probability that the output of the set bonus will drop below what one would get by simply stacking haste pieces of gear is very small.
Maybe heroic fights will make a difference, but right now even not at the haste cap, I have zero issues blanketing a raid with rejuvs when needed. I also have zero issues casting a 1.04 second nourish if needed.
In 25m I agree with everyone else, great bonus. In 10m though, while I'm not opposed to using it and probably will just out of lazyness of not having 10m and 25m sets, the bonus just seems rather trivial. Rejuv crits at least made tank healing output higher, or made the raw output of rejuv blanketing higher on an aura fight.
I really wish this would have just created a rejuv even on a target with a rejuv already there. So the person would have 2 rejuvs ticking. The priest 2p and Shaman 4p both create what seems to be a stacking dot. When it gets applied it adds to the heals already on the target. No reason why they couldn't have made this just stack with an existing rejuv.