This is my take on the extremely fast Nivix Cyclops deck, ready to play post rotation, and when Theros comes out, we can only guess what kind of goodies will be able to pump this deck.
I find the biggest weakness with Nivix Blitz is finding the Nivix themselves. This deck has a few more creatures then a usual Nivix Blitz deck.
4 Blistercoil Weird: I like these, nice one drops, get board presence early. Whenever you cast a sorcery or a Instant they get +1+1. Ina Nivix deck, I don't know why these have not been instituted, can be end gaming in their own right.
2 Guttersnipe: A staple of Nivix Blitz decks. Whenever you drop a spell, Guttersnipe does 2 damage to the enemy player, all work all day.
4 Nivix Cyclops: The star of this deck. Nivix Cyclops is a 1/4 defender, unless you cast a sorcery or instant, then becomes a 4/4. Which is stackable. So you cast two instances, and he becomes a 7/4. A good combo in this deck is Nvix and Armed ( of Armed // Dangerous) It gives Nivix a +1, which stacks on its 4 power, giving it a 5, and double strike. Thats 10 damage. Thats NUTS.
3 Fluxcharger: Another card not seen in many Nivix Decks, a 1/5 with flying, unless a instant or sorcery pops then he becomes a 5/1, oh... WITH FLYING. Such a good card, it works on the same basis as Nivix, without the stackable damage per spell. But with Armed // Dangerous, once again a easy 10 mana. Throw on a Mizzium Skin and gain 0/1 and Hexproof. Good times.
1 Niv-Mizzet Dracogenius, Prolly not the best creature ever, I might toss him and throw in a second Ral Zarek, but I like him to help dig into my deck with his ability.Then he can swing for 5 (with flying) and draw a card anyway. A bit of a late game card, in a deck where you wanna end the game on turn 5 or 6.
3 Mizzium Skin: 0/+1 with hex proof? Nuff said, also VERY cheap overload.
4 Shock: Cheap, throw away instances that you can throw away to pump your Nivix, they can counter smaller creatures, but other than that, its shock. What else is there to day?
2 Epic Experiment: Izzet is all about gambling, Epic Experiment is definitely that gambling card. Tap X cards, pull x cards, and play any instances with converted mana cost x or less for free. Its definitely a card you play when your up against a wall, or grasping for straws.
2 Teleportal: a card I need to make room for a full set for. This is variably replacing Artful Dodge. It pumps your Nivix for +1/0 and your creature becomes unblockable. Such a good card for this deck, I think I may drop the next card on the list and sideboard it for MOAR.
3 Turn // Burn Hardcore removal, basically anything thats a creature, will die. Not sure if it fits with this deck, playtested it a bit, and I think some things are left to be said.
3 Flames of the Firebrand: Nice bit of burn that allows you to deal 3 damage to up to 3 creatures in any combination. Versatile, has its uses and as always a trigger for Nivix.
4 Armed // Dangerous : Pumped enough, Armed is the death knell for any opponent, especially if mixed with Teleportal. Nivix becomes 4/4. Teleportal makes it a 5/4 and unblockable. Armed triggers Nivix to gain another +3/0 and a +1/+1 making it a 9/5 Unblockable with Doublestrike.
WHAT THE EFFFFFFF
To top it all off, the all elusive....
1 Ral Zarek.: Hes the pimp of Ravnica. His +1 allows you to tap one permanent, and untap another. ( Pssst, that means LAND too) He starts with 4 Loyalty, so his -2 can do 3 damage to target creature or player right off the bat. and his -7 which is reduuunkkkulous. Flip 5 coins, take a extra turn after this one for each coin that comes up heads. Thats pretty much end game.
Let me know what you think, I'm going to be throwing together a sideboard here shortly, and give me ideas! Lets make this the best Post Rotation Blitz deck we can!