I'd also like to add that WHM in 3.x is only neutral on mana if you're a Sylphie. If you actually contribute to DPS, you'll have a much harder time managing MP. This was the reason SCH was so valuable, alongside the Faerie, in off-healing. Their playstyle required them to use DoTs more than nukes, and as those are more MP efficient and AF was better, they had a much easier time with sustained damage. Regardless of having the lowest DPS output of the three healers.

With their DPS rotation now also being similar to the other two, add DoT's and spam a nuke for days, that's going to be another increase in MP usage that SCHs previously didn't need to deal with. So it's a valid speculation that a WHM issue has been addressed alongside a SCH strength getting nerfed.

And in theory SCH in 3.x did have the best single target healing, it's just that we didn't need to use it or waste our resources on it. Physick combined with Embrace and potentially three Lustrates per Aetherflow was not something that AST or WHM could match.