Power Infusion makes the personal CD count identical - and amusingly if you can teach your raid to use it Lightwell is vastly superior to Lightspring. I made my guys do it in HDS, it's not impossible!
Also of course Method has to take a bunch of healing classes. Only if a class is truly terrible would you exclude them as sharding progression loot is going to hamper your raid much worse than bringing a slightly suboptimal class.
As for Rejuv vs PoH we will have to agree to disagree as going from one to the other I'm always fumbling for my nonexistent Druid PoH equivalent after WG is on CD.
Okay, the cooldown count becomes identical if you factor in PI. What about the other factors I listed? What's the Holy Priest equivalent of Symbiosis and Rebirth? Also, this isn't a comparison between Lightwell and Lightspring, but there's a reason no Holy Priest uses into the 'vastly superior' Lightwell.
Of course every guild has to bring a bunch of healing classes. But if a world first 25m guild brings two Resto Druids, you cannot really argue that there's a major issue with Druids, especially since such guilds tend to be more inclined to class stacking.
Also, your personal feelings about PoH and Rejuv doesn't change the basic mechancal nature of these heals. Can you explain to me why you think Rejuv doesn't serve its purpose as a raid heal well?