I was the one that posted about Thrall's honor, and I was gonna say my opinion on the events to come but held back. Here is my most logical thought process one what will happen in the coming months:
EVENT ONE: The Ashen Verdict (Faction: Argent Crusade + Knights of the Ebon Blade) and the heroes of both the Alliance and the Horde will begin their assault on Icecrown Citadel.
EVENT TWO: If you are Horde, you'll see Varok Saurfang die at the hands of his son-turned Death Knight, as he is unable to hurt his child. Whether or not he sees his son's soul / mind redeemed remains to be seen, adding to Thrall's contemplation of honor.
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NOTE: Jaina Proudmoore is not rumored to appear as an interactive npc, as Sylvanas Windrunner isn't. Though it is likely they will be there, I highly doubt either will perish, though my thoughts on an Alliance lore toon dying are shady.)
EVENT THREE: Tirion Fordring will sacrifice himself in the Lich King fight, killing himself and mortalizing the Lich King for kill.
EVENT FOUR: "We have all left something in the snows of Northrend." On the way back, Thrall will contemplate peace and if there can ever be such a thing. Seeing so many perish - including his friend and friend's son - he fears for his people. Unwilling to command at the time of war, he puts Garrosh, who has shown growth in the final days in Northrend, as temporary warchief for wartime and travels off.
EVENT FIVE: Cairne WILL die, but it will not be known to the public for some time. I DO unfortunately believe this - though it may just be the lore side of me. Several possible ways:
1.) He decides to travel with Thrall, thus fulfilling the "Thrall and Cairne saving orphans" artwork shown at Blizzcon. He passes away while traveling, of old age.
2.) Option One, but he is assassinated while traveling. Since it seemed they were in the Stonetalon Mountains, the Grimtotems are possible culprits, thus fulfilling Magatha's first step in her plan.
3.) Cairne is assassinated BEFORE Thrall returns (likely, considering Baine is replacing him before Cataclysm). This adds to Thrall's guilt and causes him to go on a leave of absence.
I highly, highly doubt that Garrosh himself kills Cairne, even if he declares him a traitor. Sorry for the wall of text