Test pilots have deliberately test full-stalled various airliners without a bang-seat in the past, so it is something that can be done.
From an interview I saw with an airbus test pilot, he said that they only test a stall close to the edge of the envelope with high energy. The AF447 and air asia stall are far more lethal because the a/c has lost nearly all energy and have the engines at idle. This requires a lot more time to recover the lost energy. Clearly there is a huge difference between a best case stall and a worst case stall. I think it reasonable to want the ejector seat for a Chuck Yeager willing to take an a/c so close to unrecoverable.