Eyonix has posted some bad news for Pallies and/or Shamans on the forums: the Shaman's Mana Spring totem, while still providing a raid-wide buff, won't play nice with the Paladin's Blessing of Wisdom spell. The two mana regen buffs will essentially be equivalent, but won't stack in the upcoming content patch.
The reasoning? Eyonix says that Blizzard feels that Pallies and Shamans brought too many unique buffs to a group, and that this change was designed to pull in an either/or choice: either Pallies can hit up Blessing of Wisdom, and Shaman can go with Healing Stream (which isn't, apparently, being combined with the Mana Spring totem as we first heard) or do some cleansing with their Water totem slot, or Shaman can use the raid-wide Mana Spring, leaving Paladins open to use Blessing of Kings.
Which makes a strange kind of sense, even though lots of Pallies and Shammies will likely be disappointed to hear of one less unique buff they can bring to a raid. There is one hidden benefit here, however: since raids were previously recieving both benefits together (and now can only get one or the other), we can probably look forward to a buff for at least one (since the Totem suffers the weakness of not being portable, you'd expect it to have some extra ability) or both.