Hi,
PJ2:
There is far more to this suggestion than just installing the guage.
Due it's importance (to the wing "function") i think it "self teaches". And (perhaps) should be used in training.
I admit, it collides with Airbus SAS philosophy of "stall prevention" through "protections".
But (may play an important role) can be vital in (rare) extreme cases.
Mac
(Controversial,
)