The reason why everyone gets Crystal Tower is because its the only raid series that is required by MSQ and its the lowest level raids. People leveling alt jobs just tend to be there because of their level. Item level cheesing is a low percent as to why we get CT all the time. New players come in everyday, and there is sooo many people who don't unlock the other alliance raids. So unless the MSQ ties them all together; just expect a lot of CT raids.