No spectral sight is not game breaking, Every class has a counter, Yours is demon hunters, Rogues went uncountered for the majority of the game itself with the exception of paladin tanks due to retribution aura and holy shield.
You have a counter
This is normal
It’s normal to be countered by something
It’s not the end of the world
Demon hunters have a counter too, Right now it’s destro warlocks and paladin tanks and to an extent frost mages.