Best 4 person all caster/priest group

[Nostalgiabait]

Being purely practical about it, 3 enchanters and a druid would be a hard team to beat.

They'll get to where they need to go, and they'll be there first.

Encs provide CC and superior DPS via charm. No other class configuration of 3 characters is going to be able to do either one better. Druid can heal well enough on casters, and can evac if TSHTF, snare prevents runners. Outdoors you can harmony to utterly trivialize everything.

The only alternative that's worth looking at is Enc x3 + cleric, but given that seemingly everyone has a high level cleric alt to log on at their convenience for rezzes, that's not really a real-world factor.

Enc is just an insanely OP class and can handle everything besides healing. So the question is which healer do you want to add; any of them would be perfectly fine, but the druid brings the most support skills to the table by a fairly wide margin.