All of my students are taught the minimum requirements for their rank. Most of them are taught more than the minimum - how much more depends on age/maturity, time for practice, physical and mental skills, demonstrated ability, etc. - in general, I take them as far and as fast as they are ready for, but not all students go the same speed, for the reasons given as well as others. In addition, some techniques require more time to master than others, and I tend to teach those earlier than required, so that students have more time to master them before they are required to demonstrate them in testing or tournaments.
I couldn't agree more, eventually, if they stay around long enough, they will know the whole curriculum. I also encourage them to cross train, and share what they learn elsewhere.