Early reviews suggest that Vampire Madness isn't quite there. Insolent Neonate though, is a very intriguing card. I've churned out a number of Neonate lists, and am very excited to find the best shell for this subtly powerful vampire. Today's deck combines the subtle power of Neonate with the significantly less subtle Thing in the Ice. I'm not big on the Izzet Prowess decks featuring Thing, though I do like the idea of incorporating the card in a control deck. Here's a draft of what such a deck might look like:
There are builds of madness floating around featuring Pyromancer's Goggles, which pushes the deck towards playing Tormenting Voice and Magmatic Insight. The power level of those interactions is real, though I think the interactions in this build are worth exploring. Both Nagging Thoughts and Broken Concentration are generally being written off, and I think that turning a discard into an effect slightly more powerful than cycling or a counterspell is a powerful effect- though I'll admit that these cards aren't especially efficient. Activating Jace to actually just draw while countering a spell is a great exchange.
Avacyn's Judgment is kind of a question mark, though I'm currently still experimenting with running four. It will help you win Jace wars and will generally be able to kill something on turn two, while helping you close out games when you madness it. Thing in the Ice doesn't need much help closing games after connecting once, which makes the burn spell particularly valuable.
I might be a little nuts for trying to hard to find an Insolent Neonate home, though the card is excellent here. You get in a couple chip shots in the early game, which makes it easier still for Thing in the Ice to close, and down the road you both get access to an ability that digs you towards more business while also enabling madness.
The motivation for pursuing a build like this is operating under the knowledge that Izzet Prowess wasn't good enough even when Treasure Cruise was legal, and that both this deck and the Goggles decks are more robust and feature more flexible cards. It's unclear at this point whether this build or the Goggles will perform better, but I believe that both are better starting points than Prowess.