One of my most significant quarrels with iOS 11 is the app bar that appears at the bottom of the Messages app. I never use extensions while iMessaging friends and family, so it feels somewhat intrusive to me that Apple pushes the app bar down my throat in every conversation.
Anyone in agreeance may want to try a new free jailbreak tweak called NoMoreAppBar by iOS developer Reed Haffner. Just as the name implies, this tweak removes the app bar from the iOS 11 Messages app.