Even before Gearscore, there was “link the achievement to do the content you have the achievement for”, or “show a drop to prove you’ve killed this boss before”.
When people have never played together before, the best way of killing a boss is overkilling it.
No it doesn’t. RIO like every other metric only ever claims to show experience.
People have historically used experience as a shorthand for skill, but they’re not the same thing and that’s not RIO’s fault.
The only metric that actually shows skill is logs, and that requires an incredibly deep understanding of the spec and the fight you’re looking at the logs for.
Very few people actually know how to do that, and for the few that do, it’s incredibly time consuming and it’s a pretty inefficient way of recruiting anyone except for high end guild progression.