No, it isn't.
You could both two WHM and two SCH heal in ARR, but having one of each was generally better. In HW, SCH could do stupid amounts of damage while also healing, which somewhat broke the system (and started the tend of SCH being meta for every single expansion in the game).
Moreover, the game is not just raids. Never has been. And in every expansion aside from possibly SB (though probably then, too), WHM was the single most played healer Job.
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Anyway, this is a tangent to a tangent.
People need to stop saying "herp derp always been this way" when people are saying (a) it hasn't (universally) always been this way and (b) that people don't WANT IT to be this way. Saying it's always been this way is rarely a good argument at the best of times, and then getting into fights over it when pointed out that isn't even strictly true doesn't help matters.
The fact is, people don't want it, and there is game history supporting it not being forced on everyone in the past and the game working just fine - arguably better than it does today. You can have whatever last word you want, but the fact remains that GCD healing was the ONLY way WHM healed in ARR because it didn't have oGCD heals. I'll note you have not disputed that fact thus far. Therefore, you can't say it was wrong.
Simple question: Did WHM GCD heal or oGCD heal in ARR?
GCD heal.
And WHMs were prevalent across all kinds of content - including raids but also outside of them - as GCD healers because of this. So it is not "a wrong statement" to point this out.
WHM did not have Lustrate, and had 1 Benediction every 5 minutes. And you weren't going to do all the healing you needed with Stoneskin...partly on account of the fact Stoneskin didn't have any heal component.
If you're asking for SCH to be an oGCD focused healer and WHM to be a GCD focused one, that is what the history of the game supports.
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EDIT:
Anyway, for my part - I think it's fine to have some of both. That's the point of my argument.