Rejuv will be costing about 2.8k mana with these changes. I have almost 75k mana now. So three Rejuvs is about 9k, or about 12% of my total mana. I don't see the issue, unless you're still in Wrath mode worrying about keeping everyone topped off all the time.

I let people fall to 50% or so before tossing a Rejuv/Swiftmend currently. Now I can Rejuv the tank, rejuv two people who are reasonably low, then Nourish them as needed.

The key is to know how much your Rejuv will heal for, and make sure you don't Nourish someone so much that Rejuv will proceed to overheal. My Rejuv does about 20-30k total healing, depending on how many times it crits.

Blizzard is trying to prevent the paradigm of "lol rejuv spam", where literally rejuv was all you pressed. Now, Lifebloom is required on the tank, including copious amounts of Healing Touch on said tank, Nourish is a staple, but thanks do these changes, its proper place as a necessary supplement to hots has been restored, rather than the standalone heal it's been forced to be lately.