Why? shadow bolt and soul fire are too similar in my opinion. soul fire with a molten core proc is just a faster shadow bolt. currently my unbuffed soul fire's cast time is 3.63 and shadow bolt is 2.27. with molten core soul fire's cast time goes down to about 1.81. now if molten core affected shadow bolt, and reduced cast time by 20% instead of 50% the cast time would go down to 1.81! if molten core made shadowbolt always crit and allow crit to increase damage while it was activate then the only difference between live and my suggestion is that you save on a keybind.