There is often so much to say about a text. Too much. Sometimes it feels like one could have said so much more and that students have somehow been short changed. This is not necessarily true. When teaching from a text it is better to make one point well than five points poorly. Moreover, the one point you did make was probably made better because you had more to say (even though you didn’t say it).
It is the same with music. Just because a person can play a complex sequence of 16th note arpeggios at 180 beats per minute doesn’t mean one should perform them – like this:
But being able to play a complex sequence of 16th note arpeggios at 180 beats per minute makes the one note that is actually played sound better.
So, don’t scrimp on study even if you might scrimp on lecture.