After watching the movie (many times) and perusing multiple movie-related stories, comments and forums, I find myself asking - why do so many people think the Storm King is dead? I certainly agree that he is no longer a threat to anyone, but I find it hard to believe that he is actually deceased in the clinical sense. Below are the reasons that I believe support the idea that the Storm King is still alive:
1: When the Storm King shatters, his eyes flash. Go back to the invasion scene near the beginning of the film and you'll see Derpy's eyes flash shortly after she gets petrified. One character shatters and the other remains intact, but the animators made sure that both of them got this mysterious flash over their eyes. I believe this is meant to indicate that victims of the obsidian orbs are alive and conscious even after being turned to stone, and can remain so in spite of damage.
2: The first issue of Fiendship is Magic and the Siege of the Crystal Empire arc shed some light on the nature of petrification in the MLP universe. Sombra turned Princess Amore to stone and then shattered her, but he refused to kill her and reveals she could be restored one day. Whether or not you accept anything in the IDW comics as canon, I think this is a detail about being magically turned to stone that cannot be so readily dismissed.
3: A few have argued that the Storm King is dead by pointing out that his "remains" are gone when Canterlot is repaired by the princesses' magic. That, I think, is merely an animation error that can be overlooked because at that point in the movie, the Storm King was no longer plot-relevant. They didn't forget to include his broken pieces in the credits which, yes, should be taken seriously to some extent, even if there is a "Queen of the Hippos" dancing with Pinkie. Only time will tell if the writers decide to make hippos a sentient race, but we must remember that in MLP, animals tend to me much more intelligent than their real-world counterparts, even if Fluttershy isn't always around to talk to them.
This concludes my argument that the Storm King is still alive and not dead like so many fans on the internet seem to think. If you wish to comment or make a discussion of this, please do so.