It's entirely possible that the Emperor would have reacted the same way no matter how he was killed.
Dooku and Maul, if you recall, were only apprentices. It's certainly possible that his death was the Sith equivalent of the Jedi disappearing corpse technique.
As DavRobo pointed out in his answer, this phenomenon is called (by fans, nothing official from Lucasfilm yet) the 'Dark Side Burst'.