Sorry I should have included a "sarcasm" tag. I raid a lot and teamwork and communication are vital. The amount of players I helped through their first raid / challenge is very high. I have helped at least 3 players kill oryx for the first time on oryx hard challenge week. As you stated you don't have to have a defender titan but it certainly makes it a lot easier (personally I have only done hard oryx challenge once without a defender titan).