So, yesterday I said "to hell with it" and brought my incomplete izzet deck to FNM. Right now I'm missing a Guttersnipe and three Young Pyromancers, which account for about half of my creature base and some of my more powerful cards, but even in spite of that I was able to do fairly well.
I won the first two rounds, lost the third one to a very aggressive jund aggro/haste/zombies deck, and finally lost the fourth and final match on the second to last extra turn, where I had to block in a way that'd allow me to win next turn to avoid a draw... and he played one of the two remaining Selesnya Charms he could've had, which was his only out.
One game in the last match (against a junk midrange value deck, with Lingering Souls, Thragtusk, Loxodon Smiter and Restoration Angel), he got me down to 1 life, but I managed to control the game from that point onwards with just two elemental tokens and a Snapcaster Mage on board. I managed to remove each and every threat he played (even a Tusk he used Uburial Rites on twice), and got him down to zero life!
Mizzium Mortars was incredible in all moments, as was Pillar of Flame (since the ability to stop Voice of Resurgence, Geralf's Messenger, Gravecrawler and other graveyard-abusing cards was well worth the sorcery speed downgrade). I did the right thing to swap Think Twice with Faithless Looting, since it let me dig really deep for answers while feeding Snapcaster Mages, making the discarded cards not entirely useless. As I expected, Guttersnipe and Young Pyromancer were great, adding incredible value to all the spells I played, and Snapcaster Mage was a blowout due to the huge variety of instant and sorcery effects I have in the deck.
I found myself sideboarding Goblin Electromancer out nearly every single time, since it never managed to do much, so I'll probably be replacing them (on top of replacing them as soon as I get the additional Pyromancers and the fourth Guttersnipe).
On the deck's high-end of the mana curve, Firewing Phoenix won me two games that had devolved to topdeck wars (one of them was the memorable one where I stood at 1 life while brining my opponent down from nearly 30 life over ten plus turns), and the two Opportunities I added replacing the Thoughtflares were amazing as well whenever I drew them (keeping all four cards was easily worth the extra mana). I only got Niv-Mizzet once against a deck when I already had a substantial advantage, so I can't assess how good it is yet. These four cards were vital to giving my deck some late game reach once my hand was depleted and I had little to do with my mana anymore.
Hopefully I'll get my hands on the remaining cards soon, and I'll try to begin building a proper sideboard as well (yesterday's was mostly a nonsensical bunch of hate cards I happened to pick up five minutes before I left home). Finally, I'm playing my favorite guild in a deck... and it works!
It looks like the deck's going to lose two of its MVPs to rotation, though (Snapcaster and Faithless Looting), plus Pillar of Flame to get Voice of Resurgence out of the way. Does anyobody know any good cards I could try using once these two rotate out of standard?