I feel that a deck like this will sink or swim depending on what else sits down at the table with it. In my playgroup, the guys would recognize the threat this deck poses and aggro me out long before I got going. I would maybe add in another mass damage spell or two against them. I see
chain reaction and
blasphemous act in your maybe board. I haven't done storm much, but I would think you would want to gater a fair number of cards in hand to prepare to do it, so I would prob slot in
Thought Vessel and
Reliquary Tower. Decks that draw a lot of cards and cast a lot of spells see huge benefits from graveyard shuffle. I would put in
Time Spiral at least, especially since a few
Reiterate copies will generate a huge amount of mana if you have enough experience.
Consecrated Sphinx is an awesome card. It always gets removed quickly, but that is removal that isn't hitting Mizzix.
Edit: I forgot to talk about
Capsize. It is a very powerful card in Mizzix, but it tends to create games no one enjoys.