For example, if you have a 1 or 2 trainer and you train just C you will get a pop in a week with good minutes, but if you train multi positions it will take 2-3 weeks.
i've been training outside defense, with a level 5 coach and always 2 positions, on my 2 guards for 5 weeks and non of them had a pop. one has prolific and the other sensational in the outside defense skill and both have 23 years old. their potential is all-star...is this normal??
So that's nothing to do with their potential?
Passing is not a secondary training for any skill - it should not slow down outside defense training. Handling or Driving could, but I'm not sure how much in case of the two mentioned players as they have only one of those skills lower than outside defense and not that terribly.