I have notifications set to notify me of unread messages every few minutes, which is wonderful to keep me from missing a text. They're are times though, when I am unable to respond when I read a message.
It would be so helpful to have a snooze feature that would remind me to reply. For me it would be especially helpful to snooze personal messages until I get home from work or until I go to lunch. It would also be useful for those times in which we need to think before responding.