I'm a monk, I'm a
good one, and I play PuGs exclusively.
I'd rather have one monk than three. Mitigating damage
by killing mobs reduces the monk's workload enormously... Take note, those of you who run Mending "to help the monk": I'd rather you killed stuff faster.
I'm enormously in love with Communing-based Ritualists as the support 'healer' at the moment - Shelter is
awe-inspiring (and irreplaceable!) and Union is the most efficient Heal Party you'll ever see.
(Speaking of Heal Party, if you have access to a good e-management elite I strongly suggest trying it out - it's the perfect PuG 'panic button')
In order of preference for an eight-man group in a mission that's reasonably hard:
Best:
Classic healer plus Rit Lord Shelter spammer
Classic healer plus active prot monk
Classic healer plus boon-prot monk
Classic healer x2
Classic healer plus Restoration rit
Restoration rit plus Shelter Spammer
Classic healer alone
Restoration rit x2
Boon-prot alone
...
Classic healer x3
Worst
About the only circumstances I'll insist on two healers on is if (a) we have to split the team, or (b) there's a lot of suicidal NPCs to keep alive. So mainly Eternal Grove.