What about trying to teach insideShot to a point guard? You can have him work on it in practice, but when it comes to the time of the game, he really isn't going to get any practice posting people up.
Both of these examples aren't too good, since they're not universal. A PG routinely uses his IS in a Look Inside/Low Post formation, and a C shoots plenty of three pointers in a Princeton tactic.
I have to agree with WFU on this one, and have thought this since back to the beta days.It's seems more unrealistic to have a PG play at C to get training then to be able to just train that skill at the preferred position.Plus, more flexibility in training should only improve the ability to create balanced players, which is key to BB.
It really takes good managing to train effectively and it is probably the only way for a weaker team to fill the gap with reacher and stronger ones.
It isn't much different than telling LeBron that he can't start half of the time because you want someone else to also train ("I know you are by far our best player, but you've already played 48 minutes this week - go sit down").