Why do believe early 2018? I believe we'll get to play as GX characters starting 2018 in month of July so that they have enough time release characters as playable like Espa Roba, Rebecca Hawkins, Solomon Muto, Leon von Schroeder, Marik Ishtar, Tristian Taylor, Shadi, Mokuba Kaiba, Yugi Muto, Zorc Necrophades, Bakura Ryou, Noah Kaiba, Arkana, Paul McGregor, Dartz, Bonz, Ghost Kaiba, Vivian Wong,
I disagree with several of those characters. Tristan duels like once, and loses, and that was in a 3v1. Shadi doesn't duel, neither does Zorc or Bakura Ryou. Ghost Kaiba uses Kaiba's deck. We never see McGregor's Deck either. Zigfried, The Big Five, Lumis+Umbra, Raphael and Panik would make more sense.
But we do duel them in video games. Konami may be thinking of putting them in the game. But I think the Big Five will also l=make good points. We might see them as the Duel Monsters they choice. But I really want to see Leon with his Fairy Tale cards in Duel Links.
OK My bad for not knowing. I never really played the video games (before Duel Links). But yeah, it would be awesome if Duel Links introduced anime-only cards. Leon's Fairy Tales and Zigfried's Valkyries would be awesome. If they made Dartz' anime-only cards though... the power creep would be more like a power leap.
Since we are most likely getting little Yugi in the Duelist Kingdom event, I really think that they will also make a Battle City event to unlock normal Marik. When/if they release Yugi, that will prove that Marik has a chance too, because that would mean that Konami isn't using that ridiculous excuse of not releasing them out of the fear of having "duplicate characters".