Back in the days when I was flight instructing, I never released any pre-solo students for solo unless they could land properly on the main wheels. Students who landed three wheels or nose wheel first were never released for solo. This was how it was back then. Landing on the main wheels is something that you learn as a pilot right from your pre-solo days.
Thats the way it should be, back when i was under training i always landed on the main wheels, still failed the solo check twice because of unstabilized approach or not able to maintain speed within +/- 5 knots, and only when my landings were acceptable enough, i got my solo.
This is really something thats been taught in very initial days of your flying career.
