[tropo]

If it didn't happen on any test flight, the aircraft wasn't adequately tested. That sounds unsafe.

"anti-stall protection not being aggressive enough under SPECIFIC circumstances" means "not enough MCAS in the A321neo"

(there is no leeway for "SPECIFIC circumstances" unless to grant that to the 737-MAX as well)

The FAA could require more MCAS in the A321neo, and of course more testing.

[salex89]

We do not have details of this anomaly, but I hope you understand that some situations must be simulated, flying into them is difficult, maybe not possible, or downright unsafe.

I don't know how much about planes do you know (I'm starting to feel not much since excessive, maintained pitch during flare didn't tell you anything). But the context explained here is rare and obviously more manageable than "one of three redundant sensors failed and an aircraft went out of the sky without giving the crew even a possibility to save their lives".

EDIT: Found new details. The pilot has to keep the excessive pitch although AWARE that he is stalling the aircraft.