According to the game manual, cross training decreases primary training to compensate for the extra cross training. The game manual also say this
A particularly well-rounded player will continue to receive cross-training but will see a much lower reduction in primary skill training, while a particularly one-dimensional player will see a larger loss.
What makes a well-rounded player? Is it that their skills all have to be around the same level or does it mean that their skills are all high.
For instance is a player whose ratings are all 1s (atrocious) considered well rounded? And does that mean a player whose ratings are all above 10, but has large variation in their skills (ie some 10s and some 20s) is not considered well rounded? Or is it the other way around where a player needs to have a high rating in each attribute to be considered well rounded?