I spend quite a lot of time in the circuit instructing. I'm often surprised how, with an active circuit of 2 or 3 aircraft, joining traffic calls up and declares from several miles away, that they'll be joining downwind, base leg etc etc.
I really can't understand what the problem is with an overhead join in situaitons like this. It takes a few minutes more, and provides a better opportunity for the joining traffic to spot those already in the pattern. Additionally, those already in the circuit pattern know more readily where and when to expect the joining aircraft.
For solo students in the circuit pattern, there is enough going on already - we were all there once! Yet rarely do I hear traffic intending to make a non-standard join ascertain beforehand whether or not there are solo students in the circuit, before committing themselves.
I'm not suggesting the overhead join is perfect, but my feelings are that it does tend to make things more predictable for all parties.