I doubt this will happen. It would require a drastic change in the game concept. Part of the challenge of this game is allocating the right minutes to maximize training. Pretty unrealistic for a basketball game or any sports game, but that's how it is. Allowing minute allocation would simplify the 'training challenge' and reduce that aspect of the competition. I'm not sure the developers want that.
What would make the game a lot more realistic and, ahem, fun, is if this dependence of training on minutes was removed altogether. These issues of stamina and minutes played really stem from this training -> minutes correlation. Unless that is changed these issues will likely continue.