'Attack on Titan 2' news and update: Sequel is expected to be delayed?

"Attack on Titan" director, Araki Tetsuro, has already confirmed that the next installment of the franchise is still under development. However, fans are a bit disappointed about what's causing the delay, especially those who have been playing the game since it came out in 2013.
On his part, Tetsuro admits that bringing the popular manga series into a much larger audience is pretty challenging because of its impressive storyline. He wants to be able to portray it as it is.
"It's rare to adapt manga with a storyline that's this impressive, so I will be extra cautious. Whether it's season 1 or season 2, I'll be mentally prepared to face the production challenges," said the director during an interview with the popular Japanese magazine, Bessatsu Shonen.
"To animate Shingeki no Kyojin is a cultural undertaking, and because I understand that this is work that will have historical value, I absolutely cannot make mistakes. I'll continue to treat it as an extensive series that requires much in-depth investigation and design," Tetsuro added.
He also said that his team has been working with Isayama Hajime, manga author, to polish the project before announcing its big release. Rumor has it that Hajime is actually one of the reasons why the upcoming sequel is experiencing some delay. According to reports, the production was stalled because the author failed to finish the four-story arc, which is supposedly completed ahead of time.
Meanwhile, the second story arc is already complete but the director will wait for the full content to finish before the team can continue with the production. He added that they are trying their best to deliver something great to the audience once it is done, at the same time; he wants to make sure they put on a remarkable season two of the series.
For now, what fan can do is wait for further updates. No specific release date detail have been provided by the production team.