Having flown for almost thirty years and opened doors from the outside for most of them, I am now of the opinion that the main fwd doors should NOT be opened from the outside by Flight Deck or Cabin Crew from the air stairs. The above mentioned incident occurred to a colleague and he has not flown since due to spinal injury.
The B737 fwd door in particular is very dangerous in windy conditions. The platform/step to stand on is far too small to be safe and the angle of the stairs too steep to be safe without the fully extended hand rails.
Far better and safer is to open the door from the mobile stairs provided by the ground handlers. Then the platform is large and stable. If they are only at the rear door then that should be opened first and the fwd door opened from inside.
If you think differently, fine, but next time you open the fwd door in the wind and rain from the top of the stairs, just remember what has already happened to a pilot and realise that it could so easily happen to you.