I tanked Ifrit a number of times yesterday and found it much easier with a PLD and with a handful of other playing using jobs, compared to when I was a GLA.

In my opinion, a PLD shouldn't have to prioritize MP recovery. That's the mages' job. The BRD should be using the MP regen song on healers so that THEY can do their job of keeping the tank alive. As a PLD, I used my MP only for healing myself when my HP got relatively low, and also for casting Stoneskin on myself. Doing this, the lowest I got with my MP was just around half.

That said, potions shouldn't be underestimated. But if your priority is maintaining enmity, you *could* keep curing yourself and using ethers to compensate for lost MP... or you could just use a Maddening Potion.