I agree with you, the best way to train rookies its to train them in combos trainings or so like JS-JR-1vs-passing etc switching week after week. Only i would waste 4-6 weeks to train OD in a row, but not all the season.
@Skullator
Someone here also said you this before, if your league is not really competitive(i dont know exactly the level of your league) its not really necessary to train a player to 12 in OD, when he have other skills to train like JS,JR and a bit of passing too. At this moment you are losing more than winning with this trainining. If you wanna my advice, leave the OD training and start with JR 1 position, trainings on JS and(i would advice to do it in SF-PF so you increase his IS) also 1vs1.
@Superfly Guy
I dont really think this rookie is the best to make what you pointed. Triying to make a defensive beast so early when his ID=2(i suppose he poped in ID from the OD training) its not the best idea, everytime he face a PG with a nice IS and driving he will be in troubles. As i said, this rookie with his inside skills would not make a high value on the TL even if he is young.