Topic Difficulty is relative
I never understand why people feel they need a game to be easy, for it to be fun. Difficulty is relative.
If you want an easy relaxing run, do a normal mode instance, or a low lvl instance. Only inexperienced/undergeared lvl 80s will find normal-mode Throne of the Tides challenging. Everyone else has the option to take it easy.
If you want a tough run, do a heroic, or a higher lvl instance. Only super-pro/overgeared lvl85s will find the hardest heroics boringly easy. When everybody has raid gear (which could be in a matter of weeks!) maybe they will seem easy, but who knows? For now, everyone has the option to be challenged in 5mans.
So whats with all the QQ? If healing was made easier the "average difficulty" (somewhere inbetween boring and brutally unforgiving) instance for your gear/skill level would just be higher. This would be ok for now, but in a few weeks or months there would be a greater risk for the hardest heroic to nolonger be a challenge. When patches 4.1, 4.2, 4.3 have come and gone all this content would be trivialized even more than it inevitably will be anyway.
Just relax. Dont try to run a "heroic" if you arent in fact feeling heroic! When you are looking for a challenge, it will be there waiting for you.