There are some questions being migrated to PSE but a more appropriate proposal is on going. What's the point to migrate to PSE and 3 or 4 months after we will migrate them to another site?
Maybe the real problem could be these proposals. Or we hold these questions on SO until the proper site get launched or we should close these proposals in favor of PSE.
I prefer the first option but anyway I think many proposal on Are51 should be closed, users can't differentiate sites.
These are just the first examples.