Because SSS is a flawed concept that is far too detached from the realities of savage/ex content whilst it's current.
Picking up a rotation and doing it in a sterile environment is one thing, actually applying it in Savage is another. Not to mention SSS has no means of demonstrating the need to hold or push DPS, keep GCDs going through movement mechanics, preserving stacks and buffs through movement, multi dotting. It's not even much use for working out an opener with the fixed time limits.
It's a pretty obvious rush job in my eyes which is a shame as it could have been so much more useful and interesting than what it is.
Afraid of change imo =(