John - you make some interesting points. I'm not too worried about the standardisation issue as any half-interested student should be prepared by reading the relevant materials. The value of the GS is to deal with issues not understood, to check students understanding of the theory and to draw out key points from the material.
A decent instructor should be able to put a plan together and make sure its covered while allowing for those extremely useful digressions. If an instructor needs a powerpoint slide show to ensure they cover their materials I would not have much confidence in their teaching skills.
Moggie - I think your absolutely right!