Graceful scheduler with real hints

Hi,

I use the following scheduler filters

scheduler_default_filters=AvailabilityZoneFilter,DifferentHostFilter,RamFilter,ComputeFilter

Is there any way to make scheduler more graceful? e.g. when DifferentHostFilter filters out all available host, scheduler should try to launch instance anywhere.
Right now, instance is going into ERROR state during scheduling ('Failed to schedule_run_instance: No valid host was found.').

In current implementation, os:scheduler_hints hash is a bit misleading, because strictly speaking these are not hints but filters.

Is writing own scheduler a good idea? Do you plan making more graceful scheduler?