Don't forget that in the original opening movie right at the end Derplander's miqo'te friend mentions "Lets' give the bards something to sing of!" showing that even then the BRD job was definitely in the game's lore, but in both cases I just believe they're referring to an actual profession and not a at the time hypothetical combat class.
Another irony is that miqo'te in question actually became a BRD in the 'End of an Era' trailer too. ;)
