How would an AofA indicator allow for the fact that stalling AofA is less with flap than clean?
It's higher with flap down. That's the point of flaps. Your AoA indicator will tell you the wing's AoA. You can then decide its significance, as you do for airspeed.
If AoA was commonly used on the approach instead of airspeed, every pilot would know that stalling AoA is higher with flap than without, a fairly critical piece of flight information.
I rest my case.