As a PLD main, I love the idea of Cover, but there is a fundamental problem with the skill: range. While it works great as an off tank, if you're the main tank you've got an issue with the unspoken rule of "Don't stand near the tank". And if you wish to cover someone, it often means pulling the boss/mobs towards everyone else just to save the one guy (which, who are we kidding, is probably gonna kill himself again anyways).

Suggestion: Put a rescue effect on Cover to pull a party member towards you if you have Tank Stance on. If you have it off, then cover works as it did so it makes OT->MT cover work as it does currently.