I know this is a well known 'phenomenon' but as it stands, healers get worse as they level, now this is because most of us, as a whole, were in 251-277+ but let's call the average 264. If we assume we had 20% haste and 30% crit (some healers would have more or less, I know).. Our mana costs were also pretty decent.
The problem is, I'd rather be healing these dungeons back on 82, or 4.0 80 or especially 3.3.5 80 and I am 100% certain that my level 80 self could dominate these dungeons where my 85 is struggling.
The Holy trinity of heals model is terrible. Damage still happens fast sometimes, to the group and you're just struggling. Flash Heal and the like makes you cringe.. Using it is saying goodbye to 7% of my mana. It's very binary, either you do it right or you wipe... Sometimes the whole group will step up and pull it off, the ret pally might bubble / hosac the tank, someone might hoprot the healer. The boomkin or shadowpriest might break form and start healing too, the dk dps might taunt a few mobs to buy the tank a breather (not suggesting this but it has saved lives every now and then).
The problem is most players don't think that fast. I can tell because of what I do hear at the end of instances and have heard for a long time "Wow Whynot, great healing. Had a string of fail healers lately." or "Thanks for the HoProt Wutnot. Saved my behind."
These are dungeons. These are not hardmode raids, a little room for error would be nice.
Most people, heck most healers will not understand how they get worse as they level. It is fine that our crit and haste go down, that's to be expected, and obviously needed but people aren't going to understand why we get weaker as we level. I've not seen it but my friend has been told "I've seen 81s do this better than you (84). You're terrible.".
Dispel Magic etc costs
I'm speechless. I have 70k mana and these 3k costs are killing me. I know I know you intended this but I mean this more than anything else in this post when the debuffs kill people, you have to dispel, but you cringe when 5%~ of your mana is gone. That 5% mana could have better uses.
DIsc The fun is gone.
I'm not a bubble bot, I wasn't in wrath. Yes there were some times that bubbling was the smartest thing you could do, most famously any mode of LK, but that was a flaw in encounter design, but more often I try to straight heal. But my shields, with fresh 85 mastery / spellpower absorb like 10% of my health.. many mobs one shot my 10010 shield on a tank, let alone a clothie etc. Using bubbles properly was a fun aspect of the class.
Now I do love one thing. I love the way Inner Focus / ToT is working, it works so well with PoH. It wouldn't be fair to write this post and not thank you for that design.
Here's the thing.. Some people play tanks becomes they like being The Boss, the dude in charge.. Some are arrogant ... jerks. I had a tank today that would not stop for my mana for any reason. I told him to go to hell and left group.
Some people play tanks and healers to be the protector, because they're confident in what they do.. I'm one of those people, it's why I have 3 healers and 2 tanks. This is me and many of the people I know. They like to cover for people's mistakes in trivial content but this binary mode of near perfection or wipe is just terrible.
This post is not as well formed as I'd hoped. I'm kind of speechless.
tldr: It's just a game. Make it fun again.