I will say I think healing is fine.
I am an average player I push 20-21 keys but won’t go higher.
I have gotten all portals on my tank, dps, and 3 of them on my healer that I just recently resumed healing. All completed in total pugs.
However I won’t group with someone in a pug that hasn’t timed a key -1 level below the key I am aiming to do. Healing isn’t the issue, dps standing in stuff, tanks pulling faster than the healer can move and heal is the issue.
I find healing to be stress free. Honestly because I don’t care if people die. You need to go in knowing people will die.
My personal experience is that I do make mistakes and sometimes people die. Like for example I was running freehold. The last pull before the first boss has the two enforcers who have a front cleave and a bellow that locks you out of casting from that school of magic. I made a decision to try to heal someone from the previous pull to get them topped off during bellow. The bellow beat my heal so I got nature locked. Then the second bellow went off and someone died. I will take blame for this because had I not got nature locked the 2nd dps would have lived.
I think the problem currently for healers are the affixes, coupled with tyrannical or fortified.
To many times are there group wide Aoe group debuffs that need to be dispelled but also having to dispel the affix, cc the affix, run from roots etc. all this while trying to heal through the potent debuffs.
The common misconception is that these affixes are healer only. But when you get into a group that other people are doing it to it goes so much smoother.
On my monk I spec for the affix by relocating one point, same for my paladin. I lose minimal dps but make the group more successful.
In closing I would say that if you struggle healing then you need to check a few things, your key bindings, learning how to heal, secondary stat choices, and groups you decide to be in. If you join a 20 key with a 415, you have to be able to realize that they are going to lack the stam to take any mechanic and survive this means more heals dedicated to them or just leave the group