So I've tested this out by going into the editor and giving my team 20 on every facility possible, and all the regens I get are always rubbish, what factors go towards getting good quality regens?
And it depends on your Head of Youth Development and your Assistant's judging potential ability is
P.S. I'd suggest ignoring the starts given to your youth candidates, if they have good attributes for their age, if you sign them they normally shoot up. Had loads of players who were given 1/2 star potential ability shoot up to 4/5 potential just after I signed them