You're talking about bad players, I'm not. Only people who don't know how to play melee say Melees can't sustain AoE.
According to your anecdote your two monks went through 8 elixir fields (4 mins) before the pull was done, sorry to say this but monks didn't aoe, and neither did the healer it seems, and probably not even the tank outside basic enmity.
Like I said before this is math, there's no argument to be made, you will do more dmg with aoes than with single target skills once you go past certain amount of enemies, this is not up to discussion, if monsters aren't dead after 30-40s one of the dps isn't aoeing, I've never had to use elixir field more than twice in a big pull even in DF, and that's 30s.