While I get what you're saying and its kinda true... every screwed a run I've had has been because of people (myself included) taking mechanics to the face, not because the DPS couldnt DPS enough.
There are very few enrages that require the high levels of optimisation parsing is intended for.
The question high end groups need answering is how well players pick up and learn mechanics. Once a group has mechanics down and arent making too many mistakes with those you're probably clearing.