I would love to see, as tufft suggests, minor league coaching matter to the outcome of DiTRs. You know, player with Type C skills but high Makeup has 0.5% chance of becoming DiTR if he has top-10%-quality minor-league coaching for two consecutive seasons, or 2% chance if he has quality coaching for three consecutive seasons. I don't know how complicated the code would be. But as a product, it would make a lot more sense.
I think it's perfectly reasonable to ask the game to keep evolving. And perfectly reasonable to accept that it takes time to do so.
And on the topic of quality DiTRs, I've had a couple pass through my system.
Willie Javier hit 30+ HRs four times, was an AS, and won a GG.
Dicky Kwon is a pretty darn good short reliever.