The risk I see, and train against, is that of the pilot who... ..fails to make allowance for additional factors which may further degrade their aircraft's capabilities....
Absolutely. In the circuit (ie close to the ground) turns have to be well handled and allowance has to be made for turbulence for example. But the "downwind turn" is dangerous because of the optical illusion that the speed has increased as the turn is completed and the pilot raises the nose to compensate, so reducing airspeed. Balanced turn, constant attitude and airspeed - thats what you teach, no?