In many spiritual traditions, they set up a relatively harsh path for the students. It worked then – in that culture and for those involved in it – although may not be appropriate for most people today.
Most past cultures had a strongly authoritarian bent. The student was expected and willing to – figuratively or sometimes literally – give up their lives for the teacher. They accepted a large amount of abuse.
Today, we are in a different culture, with different expectations and configurations of the personality. Most people expect mutual respect and responsibility in the relationship of guide and traveler. We are not willing to give up all autonomy, and not willing to have a one-sided relationship with a teacher.
So the spoonful of sugar approach may be more appropriate, and equally effective if done well.
The Big Mind and Breema are two examples. Both have old roots, yet seem especially well suited for people in contemporary society. They are enjoyable and even fun, while easing people into resting in awareness and a more transdual way of experiencing the world.