A little advice - don't make your own argument a fallacy by referring to something which isn't in even in the game yet.
That was a supplement to my argument, not the argument itself. Therefore no fallacy. There's a reason why I used the word "also." Fact is, right now there is no hybrid healer style. There hasn't been one since they disabled the ability for you to take a bunch of talents in multiple trees and gave the healing trees huge healing bonuses in the form of passive boosts and healing oriented Masteries. Mists merely seems to be the final nail in the coffin.
My guess is you're playing in a 25M where there are less roles to min-max, less hybrid utility overall, and your buffs are made redundant as a result of homogenisation. I play in a 10M where Shadow Priest Hymns, dps Druid Tranq's and my Rains can help the raid get across the line.
25s still make use of things like Shadow Hymns and Tranquility from Balance and Feral, and I do occasionally healing rain, but only when it won't adversely affect dps. For example, if we're grouping on Spine for the roll, then I can Healing Rain. The point of the fight is to kill what you're supposed to kill ASAP though, which means I can't do that while I'm supposed to be killing the Amalgamation. Likewise, the only time I really heal myself is Zon'ozz's black phase. In other words, using your tools is fine, when appropriate. The way you phrased your argument, however, was to basically throw every Maelstrom stack at heals, and you implied holding 5 stacks to save yourself or the tank. That's not viable.
My argument is that if they raised the damage potential for Enh/Ele Shamans there would be much less need to bring in certain classes like Rogues who do very little outside of DPS. The shear fact that Shamans can spec into a healer class would make them more enticing for 10 mans where you often switch between 2 & 3 healer encounters.
I'm not going to get into a full-fledged hybrid vs. pure debate with you here. I've had enough of that crap on the damage dealing forum. However, I will say that you're wrong here because you're not considering only the dps, which is what you need to do. When a Shaman is healing, he's not competing with a Rogue, and a Rogue was never eligible for that spot in the raid in the first place.
1-2 tanks: Pure not eligible.
2-3 healers: Pure not eligible.
5 dps spots: Everyone eligible.
If you want to argue that pures need a tanking/healing spec to get them into the raid in the other 5 spots, go argue that elsewhere. When you talk about Enhancement vs. Rogue, though, only the last 5 spots matter.