Your skill has nothing to do with a healer class/spec being meta or not. It is either meta or it is not. That is simply because of what it can do, regardless of the skill level of the person playing the toon. If you suck, you suck. That is a whole other thread for discussion.
Lol. Im not sure who you are referring to, but yeah, I personally quit healing 5-10 keys a day like I did in SL. In a couple cases on Grievous weeks–where I never ever had a problem in SL–even healing 20s at a relatively low ilevel, the group wiped on a few bosses and the healing was horrible. The HPS was garbage. If I had been better geared or the key had been lower, it would have been fine. If the others in the group had pumped high damage and nuked the bosses fast, that also would have made those fights easy. Furthermore, if people did not stand in fire, used defensives, offhealed, and so on, no problem. That said, for the same ilevel and key level it has been fine–even a cakewalk on a resto druid and an evoker–both of which I have rarely played in comparison to my play on disc. That is simply because they both pump high HPS for relatively little effort, plus both have incredible mobility. That in comparison to disc–on which I have healed in the thousands of keys on. Hence, you are grasping for straws again–at least in my case. And I can say with confidence that I have never in my life struggled to master any aspect of any video game or a sport I played day in day out for any length of time.
I dont know if you are trolling or legit think these things or are trying to troll me personally. Yeah, disc is difficult, but when healers are rated as being S tier or A tier or whatever, the person doing the ratings only looks at what the healer can do irrespective of the people who play it and their skill level. That said, the person may qualify the information and mention that some specs are easy or hard and may even factor that in. But if Disc could do more healing and/or more damage than all of the other healers, it would certainly be a major contender for being rated S tier.
All I know is that in SL in some cases you had to spam Shadow Mend. Like when tanks did insane pulls at Halls of Atonement. That there are no longer insane tanks in the game is a stretch. I am not comparing myself to Moadmoad here either, but I watched him heal a lot of keys in SL, and he resorted to Shadow Mend spam a lot sometimes–of course followed by complaints about the mana burn.
As for my case and Flash Heal, I have not healed that many keys in DF because I found the spec to not be up to snuff. Remember that Moadmoad also virtually abandoned Disc, and was so appalled by the state of disc in Beta that in his stream he would sharply warn people to stop talking about Disc. I cant say I have used Flash Heal much at all, though. That said, I can see cases where spamming it could be necessary–as when the tank is nuts and/or the key is high. But again, I dunno. I have not healed many keys in DF so far–at least vs in SL. That is likely about to change though. So maybe ask me down the road.