Hmm. I'm thinking it will turn out like this:
1. Yawgmoth will die finally, and we can drop the Phyrexians already. Go to more Caterans and other original evil guys. The Phyrexian abominations are satisfying to kill, but they've gotten old. Enough with the whole techno-magic stuff. No more cyborgish things!
2. Phyrexia will collapse as Yawgmoth will be gone. It is already going to collapse, Yawgmoth is merely delaying it.
3. At least one member of the Weatherlight's main crew will die. That means Tahngarth, Gerrard, Hanna, Orim, Sisay, or Squee (NO! Not Squee!) will die. Rayne died fairly stupidly (I mean come on, they killed her off for little to no good reason I think, only to get Barrin massively angry at the Phyrexians/Keldons/Greel) I predict it's not going to be Gerrard, but someone sacrificing themself to save Gerrard.
4. Crovax, Ertai, or Greven will die in Planeshift (expansion #2), to show that the good guys are starting to win and to pave the way for Yawgmoth's death in Apocalypse.
5. Someone huge on the Dominarian side will die in Invasion. I have no guess as to who just yet (Urza is not very likely I'm thinking)
Anyway, these are just some guesses based on what usually happens. Anyone else have any guesses?