Here we go again to spin or not to spin. In the right aircraft with the right instructor a spin is no more reckless than a spiral dive with far less loading on the airframe. The 152 is a doddle
but yes I think it is important to spiral dive spin and all manner of stalls but i would add it to the PPL syllabus in the form of aerobatic training with an aerobatic approved instructor and machine.
There are far less important things they can trim out of the PPL syllabus to make up the couple of hours.
I would put it in the syllabus just before the qualifying X countries
It will make you a far more competent and confident pilot than those trained in avoidance who do not know what lies beyond.
Pace