So Troubadour is a new ability that Bard's get in Stormblood at Level 62.

It gives an additional buff to the re-tuned Songs that Bard has.

But I feel that the effects are a little messed up in terms of... Naming Conventions.

Mage's Ballad's additional effect increases Max HP.

Why is a ballad for mage's increasing max HP?

The Wanderer's Minuet additional effect reduces Magic Vulnerability by 10%.

Why is a minuet for wandering people helping protect them from magic damage?

If these effects were reversed, it'd make sense, I think.