Attack on Titan season 2 has been pushed to a later release date as director Tetsuro Araki and his team is currently pre-occupied with the production of on-going series Kabaneri of the Iron Fortress.
Wit Studio officially released their newest post-apocalyptic anime series Kabaneri of the Iron Fortress last April 8. Despite sharing similarities with other previous Wit Studio animes like Seraph of the End and of course Attack on Titan, Kabaneri is living up to the hype so far as it continues to get positive feedbacks from fans and critics alike.
Unfortunately for hardcore AoT fans, the spring release Kabaneri has pushed back the premiere of the second season of Attack on Titan. There were speculations that Wit Studio already booked its season 2 debut on April 16, but that isn't the case anymore.
Regarding the rumors circulating about how the lack of story materials are delaying the project, that might not be true since the manga series' next two story arcs - Clash of the Titans and Uprising arc - should be enough to suffice the requirement for a 25-episode season. In fact if there's a problem to point at, that could probably be on a technical level.
Related Story: Kabaneri of the Iron Fortress Update: Manga adaptation set for release in June
"As I get through Koutejetsujou no Kabaneri's production, I'm also continuing my work on the second season of Shingeki no Kyojin, so I have had many discussions with Isayama-sensei," Araki on the production of Attack on Titan season 2 [Bessatsu Shonen]
Still, Wit Studio appears to be sticking on their tentative Attack on Titan season 2 release date, and it's in the second half of 2016. But for now, all the attention of anime community is on Kabaneri of the Iron Fortress which many believes already exceeding expectations.
Kabaneri of the Iron Fortress is slated on Fuji TV's Noitamina programming block every Thursday at 24:55 time slot (12:25 a.m Japan Time). Amazon Prime also acquired the exclusive online streaming right of the anime series.