There is no point in this raid that either of those guns are necessary. It only takes 2 ghorn shots to drop crota's shield so more then that is a waste. There are only two times that snipers are required first is during death singer cp second is those on boomer duty. Ice breaker doesn't have an advantage in either of those situations so it is not needed for the raid. Granted those guns might have some level of usefulness but this raid keeps their unique attributes from being a must have.