Since we are getting Anna Never/Empress what are the chances for Matthew Gaul or other Big Bosses? It was stated that "Nope, Lucanor is not coming out" but does it mean not at all or simply not now? What do You think? What top end characters You would like to see?
I doubt we'll ever see any of the world leaders like Gaul, Lucanor, the Archbishop or Elisabetta as the Empress since Tactics is largely focused on the unofficial wars going on in Gaia and as Zeru says their presence would be hard to justify or explain-away unless all out war broke out. Also I doubt we'll most of the "world shakers" like Kisidan, Kagami, Nerelas, Lazarus, or any of Eljared's posse because, as you say sAdam, their presence would be game breaking.
Given that Tadeus von Horsman and Alexias (the Exterminator Angel) are apparently already in the works, some other top-end characters I think it would be interesting to see are: Alystaire Fardelys and her Selene bodyguard Alba Zimmerman, Kali the Executioner, Alexei Magus, Halion Soulbringer, Sho Ravengale (the Shogun of Shadows), and Killrayne.