Nintendo and IntSys had to KICK DOWN THE DOOR and YELL AT KOEI TECMO to put in characters who weren't from Awakening and Fates (besides Marth). I did grind for Anna Fire Emblem though.
Corrin's one of the worst protagonists I've ever had to endure. For the "epic" third route where the two sides come together it comes off more of a "what if" than a conclusion.