Why ID is rated higher than IS?
That is an easy question to answer. On offense, driving and IS help each other out. I prefer IS over driving myself. But Inside D helps shuts down lay ups and points in the paint by the other teams G's. 
Look at my starting SG...
Andrea Mainardi (8076105)  Small Forward   ....I play him at SG now...
Weekly salary: $ 25 651 
DMI: 238500 
Age: 21 
Height: 6'5" / 196 cm 
Potential: star 
Game Shape: proficient  
 Jump Shot: wondrous  Jump Range: respectable  
Outside Def.: sensational  Handling: respectable  
Driving: strong  Passing: inept  
Inside Shot: average  Inside Def.: strong  
Rebounding: mediocre  Shot Blocking: pitiful  
Stamina: awful  Free Throw: mediocre      
Experience: awful    
He is still a work in process, but with some more IS and JR and 2 pops in passing..he is going to be a beast.