Wouldn't that be like last year's Create A Legend? You could important legends into that making you have Magic Johnson or such as a My Player?
That wouldn't add anything new.
A cool thing would be, but this is VERY speculative, is full college integration, where you start on a college level and play your way into the NBA, including the Olympic games every four years.
That's just speculation though and it wouldn't be considered a new mode per say.