If you're a PLD and think you *need* buffs, you're almost certainly a bad PLD. (TP issues aside, since that's an issue for multiple jobs right now depending on the fight)
All three tanks are in a pretty good position relative to each other. I do prefer a PLD co-tank to a DRK co-tank for Midas, but the fights fit PLD better, like Gordias fit DRK better. But all three are viable, so its not a big deal.
