Thanks these are great questions. We do want to open source the scheduler but we wanted to launch the demo first. This is to get people talking about auto scaling with containers and to build what we learn into the scheduler.
I definitely agree that there is a place for auto scaling both VMs and containers. Auto scaling with VMs means if it takes several minutes to add a VM to the cluster you have to scale up early and scale down slowly. We think auto scaling with containers can help a lot here by smoothing out the demand. Lower priority containers can be stopped while extra VM capacity is added.