Acting for Two: The voice actors of all characters that sport replicas, naturally. Sometimes there's even acting for three. Justified
Significant Double Casting* All-Star Cast: Voice-acting example only, but if you go to our character sheet, where the attributions are listed, you'll notice there's only like four or five characters total that have non-blue links, no matter which side of the ocean you're looking at.
Bad Export for You: Although the American version got a Superlative Dubbing, the skits didn't have any voice overs. New Mystic Artes and costumes were added to the game, but most people agree those didn't compensate. This got repeated in the 3DS port.
Also, the European release of the 3DS version wasn't translated to any other language apart from English. Even the instruction booklet, with the exception of the instructions to boot the game, got untranslated.
Mieu: But master, I'm a boy! Luke: You sure don't sound like one!
Fan Nickname: Luke's Fan Nickname is Ambassador Asshat, for when he cranks up his Jerkass nature Up to Eleven as an ambassador to Akzeriuth. That's what happens when you give a spoiled rich kid authority and tell him that his freedom and the opportunity to work alongside his beloved father figure ride entirely on him doing an impressive job.
Mr.Ending The red haired man, that could be Luke or Asch depending on viewer interpretation, who comes back at the end
Talking to Himself: Replicas = same voice actor, thus highly justified. There's also an in-game example, when Lorelei possesses Tear to speak to Luke. As he says in the scene, they are the same person or at least the same fonon sentience.
What Could Have Been: Apparently some stuff was discovered that suggests more stuff was Dummied Out. While quite a bit of it was restored for the North American localization (and the 3DS remake), among the things found were not only un-used Mystic Arte cut-ins but also Van to be playable at one point. There are quite a few unused battle lines (all of them dubbed in the english release) that are probably unused Artes, such as:
Anise's Valkyrie Saber, Dragon Rampage and Fang Shot.
Luke and Asch's Falling Dragon and Ravaging Hell, and Asch's Binding Doom.