Bigger body, more time in the system and spent more time in the ruck. Sam is 2 years younger, lets revisit this in 2 years time and see how he is going.Noticeable difference in TDK's second efforts, and willingness to throw his weight around, vs SDK.
Also while TDK bested SDK in the loss to Carlton its not like SDK did nothing. People act like he had a 1 hit out 3 possession game.