Kizumonogatari is a movie based on a story of the same name in Monogatari Series light novel, which is part of First Season before Nisemonogatari. I don't even remember when it was supposed to air, probably two or three years ago. After the delay, they kept producing other stories in Monogatari Series like Monogatari Series: Second Season, Hanamonogatari and Tsukimonogatari.
Why did they put it off for so long? If it was because of production issue, like Hanamonogatari, why did they keep producing another Monogatari Series but not Kizumonogatari?