I find VNs without true routes to be so unsatisfying and true routes give me a reason to play all the heroine routes. Without them, I would probably quit on a lot of VNs
But I'm pretty sure there's not much doubt left in the story, also in other routes, that Kazuki is in fact dead
There's no way she's dead. The writers would have lost out on so much story and plot if they killed her.
Hi and welcome to the forums.
I strongly recommend finishing Rin's route even if you don't finish the others.
Have a great time and hope to see you around.
Itagaki siblings are part of the Agave route which is untranslated. You can only play Kazuko, Momoyo, Yukie and Chris as well as the teacher route until the rest has been translated.
I would say my favorite Protagonist from the VNs I've played so far is Yuuji from Grisaia, mainly because he has the most interesting personality and past.
Haven't really come across any really good Antagonists though.