This. The huge margin of potential downtime that makes the portion of healer globals spent DPSing is what allows skilled and unskilled healers to play the same content, while leaving both something to do at all times.
You can try to force improvement on those unskilled players, and that may even come to some success, but there's a good reason for where and how XIV has chosen to deal with derivative outputs (healing and mitigation), with both seeming largely undertuned in their requirements for most content, or overly intervallic for the remainder.