I'm an idiot who really should play more Shaman, Eyonix only said the name of the right skill FOUR BLINKING TIMES! Title updated, with my thanks to Isa in comments.
Hot off the presses we have this from Eyonix:
We are making a change to these spells so that their benefits are exclusive in patch 3.1.0. The buffs will be equivalent, but will no longer stack. Mana Spring will affect the entire raid instead of just the shaman’s party. We felt that both paladins and shamans brought too many unique buffs to a group. Additionally, we have been trying to tone down mana regeneration in large groups, and were concerned raids would feel the need to stack paladins or especially shaman to have enough Mana Spring totems. We have also been trying to get more benefits out of the party and into the raid, and Mana Spring previously was still a party only buff. With this change, if there is only one paladin, he or she can bring Blessing of Kings while the shaman offers Mana Spring. If there are two paladins and the second offers Blessing of Wisdom, then the shaman can offer healing or cleansing with their water totem instead.
Can't say that I didn't see this one coming. I wonder if another class is going to get a BoK equivalent in the future, my guess is 'probably'.