Not enough people practice PFLs often enough.
Not enough PPLs practice glide approached often enough.
If people would fly more appropriate circuits all the time (which I know at some places is not possible due to local noise abatement procedures) they would be a lot better at gauging aircraft performance and approach angles from different locations in the circuit.
I would be hesitant to advocate a completely different circuit for (P)FLs if people are used to flying rectangular once for normal circuits. Modify what you are used to rather than try to do a constant aspect approach, cause they require training and regular practice too.
If you look at accidents for FLs and outlandings for gliding it transpires that people come to grief for 2 reasons.
1. They go too slow near the ground and stall/spin
2. They go too fast and go through the hedge at the far end.
3. They change their field of choice in the latter stages.
The advantage of practising FLs is not just that you get better skilled at flying the aeroplane in a different configuration but also that the mindset changes from 'it won't happen' to 'it is happening and I am going to deal with it'
This is probably one of the reasons why off field landings in gliders are less likely to be a serious event than in an aeroplane. Everyone involved in XC gliding sets off knowing that an off field landing is on the cards.
Interestingly there is some evidence that people who fly gliders with a retrieve engine in their glider do not do so well as their engineless counterparts when the thing refuses to work. Again I think suggesting that mindset is an important factor.
I have said on here before that I think that by 500ft you should know whether you are in the 'slot' after that there is nor the time nor the room to make any meaningful changes.
If you are not sure whether you can judge whether you have it right by then you need to do more glide approaches at your homefield.
FD