Our group clears Turn 1-4 every week and is currently working on T5. We run:

2xPLD, 1 WHM, 1 SCH, 1 DRG, 1 MNK, 1 BLM and 1 BRD

Don't see why people tend to think that bringing 2 melee is necessarily harder than bringing 3 Casters/Ranged. Both setups work fine and I don't see any issue with bringing 2 melee DPS.

EDIT:
I'd say most stuff can even be done with 3 or even 4 melee DPS without making things too complicated.