I do believe we, as a class(specà, are balanced around always having a Chakra up for our total healing. But I don't think each individual spell is. A Prayer of Healing in Serenity (or no Chakra) is the baseline. In Sanctuary the extra healing is a bonus.
And I like having Chakra be able to fall off. It leads to interesting moments where you can't cast the right spell to refresh it and need to make choices, and this feels (to me) more meaningful than other choices we have to make. I know this is personal opinion, but the Chakra mechanic as it works right now (or the 30/30 one) was one of the things that I thought made Holy Priests fun and unique.