Same as DR1. None of them deserve to die. Each Character is unique and it was pretty heartbreaking seeing some of them go whether they were お気に入り of mine または not (The pain was relieved with the DR3 Anime). Guess, if I had to make a mention, I would say Chiaki because of certain circumstances of hers that differ from the rest !!!!
However, if I had to choose one who DID deserve to die, Id say Nagito XD I mean I 愛 him with all my heart, but with how he was behaving, we all knew he was going to die in some way または form.