I once took off from Perth (Western Australia) in a BAe 146, and had a cabin fan failure. This means absolutely nothing in terms of the QRH, or continuing the flight - however it does mean that, should a cabin smoke event occur, you couldn't clear the cabin of smoke.
Continued flight was fine, however the MEL wouldn't allow you to take off with the problem, and we were planned to a no-engineer port (as were most of our ports in Australia). So a "perfectly fine" aircraft (short of a cabin fire), but the company wanted us to return to Perth were we had engineering, and we were a couple of tons overweight.
The decision was made eventually to hold over the water (out of the way of arrivals) for 40 minutes with the gear down and airbrake open in order to burn off the fuel. Well the passengers became increasingly nervous about the vibration, despite several PA's from the Captain (I was an FO), including one in the cabin, and we nearly ended up with a riot - the passengers convinced themselves we
couldn't land, and the vibration was the "real problem" - in effect, they thought we were lying to them!
So that is a consideration as well!
Would you like to comment on using the safety factor of 1.67 i.e. it is required for a normal landing in routine but why not when you are making a heavy landing when it is needed more as compared to a normal landing.
The extra weight is taken into consideration in the landing calculations, the 1.67 factor is to allow for either floating (less likely when you are nervous about landing overweight) or "skidding", so the only time I would think it is "
needed more" is with a slippery runway. The weight isn't a problem.