1v1s aren't everything, in fact, as a HEALER supporting your team should be what is most important.
Oh how they use the same set as resto shamans?
I mean, pretty sure it has just as much as restoration shaman and restoration druid, I'll give you this one though because rejuv isn't really all that great for it's on cast.
This would make for an interesting test. Here's the thing though: let's say a shockadin does do more DPS than a disc priest, OK, considering they're shockadins they will have to sacrifice a lot of healing potential for more damage output. Disc priests do both healing and dps and thrive in both at the same time. Holy paladins are forced to either heal less for more damage or do more damage for less healing.
Stop looking at healers based off of what's good in 1v1s (which makes no fucking sense as a metric to measure how all around good a healer is) and look at them as all around performing specs.
It's kind of like, sure, rets are kings of arenas and 1v1s, but they're not really S tier with restoration druids and shamans because they're lack luster as fuck everywhere else.
Funny enough, one of only reasons hpal is the worst healer is because it doesn't have the DPS that the other healers have. xd