For the record, I regularly parse around 50% of 6-person party's damage on BLM in Ra'Skimish. It's very friendly to mage jobs, but you still need at least one or two melee to tank the monsters.
Also, two more things:
1) Doing a Tier 5 set seems to unlock a Fluturini NM that can cast Kaustra / Meteor and needs to be defeated with a combination of melee and magic damage. We've also seen an NQ Leafkin mob in a V/V/V set that I've never seen anywhere else.
2) New NMs sometimes spawn a few minutes after entering the zone.