Engine failure with loss of thrust on final approach/in landing configuration (requires swift action to maintain control: flap 15, bug plus 15, accurate flying);
In my company we are allowed to maintain actual landing flap setting (30/40) when engine failure on final.
Only if thrust would be insufficient we must go back to 15.
Tried it in the box and works really fine, no more large pitch and roll changes. I was told that the swift return to flaps 15 (and all handling which comes with it) dated from the -200 series.
The "modern" CFM engines are powerfull enough to produce the thrust needed to recover engine failure with flap 30/40 on final.