So far, there have been three cards in the first two sets of the current block - Azor's Elocutors in Return to Ravnica and Hellkite Tyrant and Biovisionary in Gatecrash - with "you win the game" in their text. Normally, alternate win conditions show up maybe once per block, if that, so the fact that there are this many in merely the first two sets, with the second set not yet fully spoiled, is enough to give pause. While yours truly has already asked Mark Rosewater on his Tumblr blog whether this reflects an actual, intentional subtheme in the design, the R&D head has so far been mum on the issue. But if it does, how could that be reflected in the rest of Gatecrash or in Dragon's Maze?
In terms of Gatecrash cards that have yet to be spoiled, there's already been a white/blue hybrid autowin, a monored one, and a blue-green multicolored one, meaning that the only color that hasn't gotten in on the action yet is black. So if there's another card like this in Gatecrash, odds are it's either monoblack or it's Orzhov-aligned (since Dimir would saturate the theme in favor of blue - unless that's what R&D was going for). If it's the latter, it might well play into the extort mechanic: I can see one mechanic I originally envisioned for Rakdos, Lord of Riots before it was spoiled changed to an Orzhov context. Something like "At the beginning of the end step, if an opponent has lost 7 or more life and you have gained 7 or more life this turn, you win the game."
As for Dragon's Maze, it might tie into one of the wildest rumors about the third set - the possibility of a legendary Nephilim cycle. One, or perhaps all, of them might have alternate win conditions attached to justify their strange four-colored-multicolor identities and give them some extra appeal as EDH commanders. If not that, the final stages of Niv-Mizzet's plans might be represented in card form, surely with an alt-win ability because the flavor makes perfect sense for it. But since so little is known about that set, only time will tell if any of these rumors are remotely plausible.
What do you think of the current of alternate wins running through the block so far? What does it portend? Let me know in the comments.