The WoW developers are planning changes for mana regeneration and certain buffs in patch 3.1.0 by lowering down the amount of shamans and paladins required for a raid. They want raids to have an even amount of classes participating, rather than stacking 4-5 paladins or shamans. Mana Spring will now benefit all the raid. Only one Shaman is now needed to benefit from that ability.
The major impact to how raids are usually done is that you can no longer stack mana regeneration. How is that? From what Eyonix said, what can be understood is that Mana Spring Totem and Blessing of Wisdom will no longer stack. So now the raid leader needs to synchronize which abilities must be used according to the raid’s class setup—depending on which classes are online at a given time.
If there is a shaman and a paladin, the way to go would be to have the shaman drop mana spring totem and the paladin to do blessing of kings. If there are two paladins and no shaman, one will do Blessing of Kings and the second shall cast blessing of wisdom. The wrong way to go now is having a paladin cast wisdom and a shaman drop mana spring—both mana regen won’t stack, thus wasting a group buff.
This decision could probably benefit alchemists a tad in theory, as players will want to buy mana regen flasks more often than pre-patch 3.1.
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