Just my though

I was just wondering what would be the quality of education if we had a system of teachers with their days' working hours divided equally between preparation and delivery of their lessons. In a school 50 % of the teachers would be made to teach in morning sessions and other 50% in afternoon sessions. Those 50 % who are supposed to teach in afternoon must prepare their lessons in the morning when other 50% are teaching who prepared their lessons in afternoon the previous day. But mind you, the system must ensure that the lesson preparation hours should be optimally devoted in planning and preparing lessons that all the teachers must be in the school on time and leave at the sound of last bell.
      That way, I think, there is no need for teachers to take their works home compressing their family and private times. No worries about works at the sound of last bell of day. And fresh start at the sound of first bell.
     In the present scenario, teachers plan after their last school activities when they are thoroughly exhausted often having to take some parts of plannings home. Most of us believe that quality and flow of a lesson are determined by the quality of planning and preparation hours. So how can teachers aspire to plan quality lessons when they are fully worn by their days' both curricular and co-curricular obligations?