DPS display could easily be solved with a system already in game.

[Kaisha]

Source: over 10 years of raiding in games since FFXI and vanilla WoW, before parsers were even a thing.

Didn't really need a parser in XI's earlier years when everything gave you 30 minutes at the minimum to defeat something if it was in a battlefield. Most of the relevant content was outdoors and had no such restrictions, or enrages for the matter until years after the fact.