If all three parts are this long, it'll be 180 minutes total. Which is not short at all.
60 x 3 is long for one movie. If it was three movie length movies thatd be over one season of content for one book which would be terrible. Even then 180 min is like, 8 episodes. I'm not sure how long Kizu is compared to Karen Bee or Shinobu Mail which are longer arcs but I bet they will probably add some stuff since they were originally going to do it after Bake and they have all this other content done
Yeah, it's quite long as a 180 min. movie, but as MetroidPrimeRib said, I just wonder how exactly they moved from a single movie to three. Did they have more content and that couldn't be in one movie only or they decided to add more scenes in order to have three movies? Added stuff isn't necessarily bad, and in Monogatari's case it can mean a lot of things, but still it is worrisome.