Yes that is the issue I am trying to address. What you are saying is extra reasons to make buffs raidwide, if all those buffs were raidwide it would make no sense to have 4 shammies, 4 clerics - if the druids buffs on top of that were good enough on their own then they would be indispensable for hte raid as the entire raid woudl benefit not just their group. If say druids acutally had better raidwide hp buffs than shammies and clerics, this would also help to make life easier for druids in groups (in groups the buff would be groupwide obviously).
The example I gave with the 6k group ward in combination with all healers having proper raidwide buffs is what I meant to be the solution to the problem you stated.
1st step: make buffs equally viable, so having a templar hp buff is not better than the warden one
2nd step: make them raidwide so that you want all 6 healers in a raid to stack buffs (as 2x templars wouldn't help hp for any group as all would just get the hp from one of the templar buffs)