Healers who rescue pull tanks into mobs.

[Seraphor]

This is not really true: https://www.youtube.com/watch?v=h2AhaGYoeIE (apologies for the audio it recorded my fc mates but not me)

This is doma castle, notorious for being a hard dungeon for new/ undergeared player, with large pulls (some exceptions like the giant but mostly wall/ double pulling) with the entire party at minimum item level. Through good tank and healer play the tank lived and the healer maintained more damage spell uptime than healing spell. In a case where everyone isn't at minimum item level theres no excuse not to pull big anything past arr leveling content (even then most of that is a joke too).

We're all aware that player perfomance is just as important if not moreso, as gear. Addressing ilevel is just putting it politely.
You can't control your tank, so if they're not hitting their cooldowns at the right time, or don't know how to, I wouldn't be pushing them to pull more.

Also, ilevel isn't such a good metric to go by these days as it's an average.
You could be in all i255 gear, the minimum ilevel of Doma Castle.
Or you could be in i200 gear on your left and i330 on the right. You'd still meet the ilevel, but your stats would be far worse, Vitality in particular.