Ifrit is more or less a secure kill as long as you have a stunner (Paladin) and a Mage for AoE Limit break.
This is exactly my point, having a paladin for stun and BLM or SMN for LB is almost essential to killing it. I also don't see two scholars being able to heal it, the lack of shell and extremely weak AOE healing would make the fight a disaster.

You need a certain class make up and competent players, so why does duty finder throw you into a x2 war x2 SCH double brd DRG MNK party?

The fact that duty finder exists makes it harder to form your own sever-only group, if duty finder didn't exist, you could form a group with competent players of proper set up much more easily.