I have said this on other threads and I will say it again here because it is important to hear. I have taught Kinder for 11 years, in the last 5 years, Kinder has become what 1st grade used to be. Preschool is the new Kinder.
Knowing this, Preschool was a definate YES, for our family. I couldnt be happier w/ the preschool, teachers, art, music, performances, field trips, socializtion, independence and FUN that both of my children had.
As a Kinder teacher, you can definately tell quite quickly, which children have attended preschool and which have not.
My suggestion for you is to look into a new preschool, maybe a co-op.
You are right. That is another bonus to pre-school. It is still easy and relaxed. In my DD's school (afternoons) being a bit late isn't an issue at all. Home work is an occasional fun family project. absences for vacations and just wanted to take the day off, no biggy. No true in K and the rest of school.
preschool really is about fun and can start of the idea of going to school on the right foot.