Underperfoming vs median vs overperforming?

[MirielleLavandre]

Reading through many threads, I'm genuinely wondering what people here on the forums (acknowledging that forum goers are already far more invested in playing well than probably the majority of the general population), consider 'underperforming', be it as a tank/heal/or dps?

I often get the impression some find 'median' play, or people who know the basics and play within the median, to be 'underperforming'. Is there any consensus besides acknowledging things like ice mages and cure 3 spam/no dps heals are underperforming?

Also quick edit, I'm referring only to normal trials/raids/etc, not EX or savage or ultimate where min/max is probably the norm ^^