... But the combination of "by default, tanks should pull wall to wall" and "by default, healers should spend as much time DPSing as possible" is an absolutely toxic cocktail of unapproachability and is the reason you rarely see DPS as adventurer in need for 4-person roulettes. As long as you ask these two counterintuitive things, tanks will die, healers will feel put on the spot, and both will queue less and err on the side of DPSing, trading peace and absence of higher responsibility for a longer queue.
I know you're gonna get mad, but it's true.
Healing isn't hard. Tanking isn't hard. The way people expect these jobs to be played is counterintuitive and puts "respect for everyone's time" over approachable gameplay. There's no safe way to discuss in a tank's greeting macro that "I will pull fast until I die or have to use holmgang on trash" that doesn't put the healer on the spot, and honestly, the healer shouldn't have to tolerate "everyone's wall to wall until you say you're new or someone dies." And that doesn't even work because "this is a level 80+ dungeon, how are you new, you should know by now" still happens in a world where one can use duty support from the beginning to end of the game!
Look, just be kind, ok? And don't crack the whip or pull for the tank when he's trying to take it easy on a healer who clearly needs it, yet has to say "you can pull big" to cover their ass.
Overly DPSing healers are a bonus.
Wall to wall pulling is a bonus.
They're perks, not entitlements.
Just be kind. You're all so good at that when people conform to your expectations, maybe alter those just a bit to err on the side of kindness.
Thank you.