Yes off course. But how is it with Rampant Growth?
Based on my unbuffed tooltip values: Unglyphet Regrowth is at 10876*(1+0.7*2)=26102, assuming 10% base crit. Swiftmend is 17411*(1+0.1*2)=20893. 2 cooldowns heals for 20893+26102*2=73097 for a cost of 4160+5962=10122. HPM is 7.2, HPC is 36.5K. Pure glyped Regrowth spam gives 10586*3=31.7 K HPC, and HPM 5.3.
So Rampant Growth with unglyphed Regrowth is indeed better for single-target healing than glyphed Regrowth-spam, not much HPC-wise, but by quite alot in terms of HPM. That's certainly interesting - I'm not sure how useful those last 3 seconds on rejuv actually is and I don't use the added Germination HoT that much. Having the option of doing +50&% Wild Growth on cooldown could easily be worth more. This should definetly be worth trying!
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I think that's what rejuv comes down to - being able to preheal, and heal on the move. In terms of efficiency it's not a particularly outstanding heal, and if healing is needed here and now Regrowth is just better.
If you have the mana and it's quiet, why not rejuvblanket?
And one more thing: Since Regrowth spam beats Rejuvenation blanketing with Incarnation, Incarnation is a rather weak healing cooldown (+15%) and more of a combined healing/mana cooldown. Nature's Vigil is a stronger healing cooldown now that we mostly rely on single-target healing.
Edit: Tried one run now with Rampant Growth + Soul of the Forest, it feels really good. One point Hamlet made in one of his recent podcasts with Perculia is that as a healer you want flexibility. That talent combitation gives you an amazing amount of flexibility. And there's the element of finding a HoT with short time left to eat. I scales well, unlike glyphed Regrowth, which doesn't benefit from crit. And it's bound to be powerful in a raid setting. The drawback might be mobility limitations.