Nothing is inherently wrong with how healing works, but optimally you play a healer to heal as little as possible, which is easily anathema to why you pick the class in the first place. Many a discussion I've seen in regards to WHM and Lillies said the mechanic promotes bad play, that is to say, using GCDs to heal instead of damage. To play a healer at its peak potential is to actively DPS and try to shelf active healing as much as possible (That is to say healing via oGCD and mitigating damage so as to hard cast heals less).

Role Priorities are pretty weird in this game.

DPS: Damage>Damage buffing Utility>>>>>>>Defensive Utility.

Healer: Healing>>>Mitigation>Damage Buffing Utility=\>Damage

Tank: Aggro>Mitigation>>Damage.

As I said before, DPS do absolutely everything in their power to live up to their namesake, and it shows in the depth and design of DPS. Tanks are always gonna spank, which is why Tank DPS isn't that hotly debated (Just tank stance which falls into mitigation), and their rotations, well, exist, but aggro is a joke and, as the TC pointed out, damage only spikes, so mitigation isn't super important most of the time (We'll just shelve tanks).

Then we have healers. Once everyone is topped off, you do your DPS. Even when things go a little nuts, you blow a few oGCDs and spam your respective cure 2. This goes back to basic design, but the question in this game isn't, "How should I go about healing this moment," but is instead, "Am I done healing," and honestly, the latter is inactive and can be boring. You either wait around or pop a dot. It being "boring" is subjective, but it is not nearly as engaging as a tank or DPS is, and I don't think making them more like a DPS makes sense.