I think all early circuit training should be done in gliders.
We use motorgliders to practice field selection prior to cross-country. I think power schools should make arrangements to fly a series of glider circuits before solo to show power pilots the correct size of a circuit, just in case the engine stops.
Given many pilots failures to recognise carb icing, it would be a salutary lesson if the instructors chopped the throttle on a long low fianl approach once in a while