You must be ether new, in denial or have short term memory cause Cata and Mop healers were damn immortal, like literally you would have 1 or 2 deaths at most in pvp and thats if you were a bad healer, also rdruid and hpld have been the damn go to go healers in arena since tbc, hell rdruid/war was the reason why 2s were taken out of end of season rewards/titles.
You're that type of person that says "remember when plds were op in wrath", and I'm that type of person that says "oh you mean horde plds cause they had seal of blood which to this day is still one of the most bursty seals plds ever had, meanwhile alliance plds had sot, a wet noodle hitting seal that had a ramp up time of 15 sec".
Don't try and pull a made imaginary event in wow pvp, I've been pvping in WoW since 2005
If they went back to mop style healer survivability they need to bring back high cost heals of wrath and the tbc/vanilla ms debuffs. As for dps the need to drastically bring back dr on stuns, give healers a disarm ability/spell (example, holy plds can have a "flash" that disarms a target for 4 secs, a resto shaman can have a "tremor totem" that shakes the ground to disarm targets).