The title of "Canada's Pride" is currently in dispute. On one side you have the reserved, soft-spoken Jon Stern, who found international recognition after his win at Grand Prix Atlantic City, and who broke into the Top 25 Rankings shortly after their inception thanks to his constitent strong finishes. On the other you have the (comparatively) flamboyant man-about-town Alexander Hayne, hot off a Grand Prix win in Kyoto with Hron and Hoaen, and looking for his third trophy of the 2013 Season. Unable to choose between these two modern Odysseuses I sought their combined wisdom about the ins and outs of Theros sealed.
For both, the format begins with blue, and specifically the two commons Griptide and Voyage's End. In a format where removal is either situational or expensive these two spells rise above. Hayne further broke it down by saying "If you look at this set, it's all about creating a single large threat - Monstrous, Bestow, and Heroic all push towards that." Giving blue two common ways to thwart that puts it way out in front of the other colors. Hayne went on to say that in a format where people are making big monsters, your best bet is to have the biggest monster, which usually means playing green. The gold standard is Nessian Asp who also shuts out the skies as a route to victory. Jon Stern sewed it up with this quote.
"I've done around twenty sealed builds, and probably sixteen of them have been blue-green. I'll try other builds, lay them out, and they just look terrible. Even a bad blue-green is often better than a decent deck of other colors." - Jon Stern
To me, the next logical (if naive) question was: Can't fast decks punish the focus on big creatures? The short answer is that sealed is not draft. You'll very rarely have the cards to consistently execute a game plan of hitting your first three drops and backing them up with tricks. Without all the pieces, those decks struggle with draws that don't come off the blocks fast enough, and then their late game draws are just worse than their opponents'. It's much easier to build a deck that consistently takes advantage of the middle game. Stern said "It's easy for creatures to get obsoleted on the board." Hayne added "Even the tricks that are available don't let you trade up." Titan's Strength might let you cut down their Asp, but you'll still lose your creature. Another interesting consequence is that Dissolve is a lot better than its analogues were in previous sets. Stopping a single Sip of Hemlock or Divine Verdict is often enough to put a game away.
I asked them if there were any common pitfalls that trip up those less experienced with the format. Stern pointed to the wealth of mana-fixing in the format, with Traveler's Amulet, Opaline Unicorn, Burnished Hart and Unknown Shores available for all colors. Stern says players are often seduced into splashing a powerful card without considering the space that fixing takes up in their deck. "The question I ask is 'What cards does the fixing replace?' Often those cards have more value than the splashed card and its support."
Hayne said that the easiest mistake to make is playing your 2/1's for two mana. In addition to being outclassed as early as turn three, they run into a lot of the common removal such as Lightning Strike and Pharika's Cure.