Why not an ingame damage tracker?

[Xaphire]

Personally, there already is an in-game damage parser.

When the final boss dies, that means the DPS was satisfactory. :3

This is true of easy content. It was important to know who was pulling their weight and who wasn't when we were progressing through coil in average item levels of 60-65. The use of them also helped find meaningful number for gear choices to maximize output.