Tools they could add besides DPS meters... (For endgame)

[Rilifane]

I love how in these discussions it's never okay to expect basic competence but completely fine to put additional pressure on the rest of the party.
If someone is barely performing at the required level, then happens to "just not play well" and drop even lower, requiring the rest of the party to make up for it that's completely fine, world didn't end, so what, don't be elitist and mention it.
If someone had to play at a much higher level to make up for the above mentioned, they better keep quiet and don't they dare feel frustrated by it. Damn elitist. Just feel blessed that you had the opportunity to carry others. Give yourself a silent pat on the back but keep your head down.