Bards, but they're no more melee than shaman.

You're basically looking at 3 factors here:

1) Can you single pull the mob or CC? With root nets and a bit of micro, you can manage to split some with any class.
2) Can you heal?
3) Can you slow? Monks get access to a charged slow stone, but this is basically just rangers and warriors.

I'd argue rangers are the best provided the mob comes solo due to Earthcaller and the ability to root -> heal. If you factor in root nets and slowstones, monks come out ahead.