1. The PAPI angle may be different to the approach angle I.e. 3.5 degree approach with 3 degree PAPI. Once you've gone around for one of these on an NPA with cloud close to minimums it hits home.
2. Your ops manual should stipulate stability criteria. On the A320 in easy we are considered unstable below 500 if VS is greater than 1000 FPM on a 3 degree +/- 150 FPM per half degree change in glide path. So if on a 3 degree you need more than 1000 FPM below 500 for anything other than transient stability then you need to go around.
3. The PAPI is calibrated for different aircraft - An A320 being Cat C. In NCE on runway 04L the PAPI are calibrated for CAT D aircraft. The amount of times I see my colleague religiously stick to 2 reds 2 whites when it isn't necessarily appropriate I've lost count on.
4. Below 200' the only thing that matters is the aim point. Completely ignore the glide slope and the PAPI. In my opinion your colleague calling 'glideslope' or '3/4 whites' inside the last 200' will be why there inexperienced colleague does a hard landing.