Actually, it sounded better as Janos assassinating the LCotNW after Jon (who very well could be Cotter Pyke). That is something that Janos would attempt.

However, I can't see that happeneing. First off, GRRM is famous (infamous) for defying all convention in this series. Anyone willing to kill off major characters is not going to do something that likely has a trope associated with it. Also, as Samwell puts it in the the series, even though they refer to Jon as the 998th Lord Commander, records put it closer 600 or 700 something.

I also don't believe that Jon would leave the Wall for any reason, and especially not for Stannis. If anything, I could see Stannis throwing his weight and men around to force the Watch to his control (though it seems almost out of character) and then for Melisandre' to step in and throw her support behind Jon. Actually, I don't see Stannis making his way south at all while the Others are massing. He came to the wall to fight the Others, so his case will be more about convincing the rest of the kingdom the threat is real and he's the Lord Protector of the Realm.

The Wall will come down by the end of the series.  As long as it's up, the Others aren't much threat to the Seven Kingdoms.

My prediction: ADwD will chronicle the return of Dany to Westeros, conquering the Seven Kingdoms with her dragons and the Unsullied.  At the end of the book, or the beginning of The Winds of Winter, the Others will get their hands on the Horn of Winter and bring down the Wall.  The Winds of Winter will cover the war between the Others and the people of Westeros.  Dany, Jon, and the third head (Tyrion or Darkstar, probably) will ride Drogon, Rhaegal, and Viserion against the armies of the Others.  The Greyjoys and their bannermen will fight the Others on the seas.  Stannis and his Asshai'i host will fight the Others with the magic of R'hllor.  Howland Reed will finally show up and kick some ass as well.

The war will rage through TWoW and into ADoS.  At the end, the Others will be defeated, but the long winter will not be over yet, hence the title "A DREAM of Spring"... Spring isn't here yet, but with the Others gone, the winter won't last forever.

When the dust settles, Stannis will be dead, Jon will be King of the North (Everything north of the Neck) with Mance and the former Wildlings as House Rayder, Darkstar/Tyrion/whoever the third head is will be King of the South (the Neck to Dorne), and Dany will be Queen of the East (Braavos to the Shadow).

 OK my prediction:

(1) Dance with Dragons

         - Dany's control of Meeren will collapse as it did for Cersei. She will end up losing her Unsullied, her dragons (to Victarion), and Barristan. At that point Quentyn will take custody of her and bring her, Illyrio, Tyrion to Dorne. 

         - Victarion will take the dragons and use them to pillage Westeros and kill Euron. 

         - Reek (Theon) will watch Ramsay marry and torture/kill "Arya Stark" and see his sister killed by Boltons, at the end he will forget he's Theon. And he will be the POV that we see the Bolton's reassert control over the North.

         - Cersei has chapters, so I assume its either a trial and death, or she gets rescued but loses all the power she had as Kevin takes control of King's Landing.

         - Arya adapts to being blind. She's abandoned by the temple and becomes a beggar.  

         - The battle between the Others and the wall begins, and the wall falls (clifhanger at that point).

(2) Wind's of Winter

         - Dany schemes with Doran on getting back her dragons. But then realizes the Dornish are just using her. This becomes moot when the Lannisters fall anyhow.

         - Victarion manages to plunder most of Westeros except Dorne, and the north.

         - Sansa kills Littlefinger, takes control of the Eyrie, and then is taken as a salt wife by one of Victarion's men.

         - The north is overrun to the neck, but then only a few Nights Watch and Mel escape to the south, which is a burned wasteland. Jon Snow is presumed missing. 

(3) Dream of Spring

       - Chronicles Bran returning with the Children of the Forest to battle the Others. At this point almost everyone else is dead. I suspect most of the other plot threads will remain unresolved and the question of Jon Snow's heritage will be unanswered. 

I disagree with the most annoying character is Sansa because she has not thought of her own and lives in some fantasy world were a knight will save her.

Winds of Winter

• The North finally becomes aware that the Others exist and are an imminent threat. The Boltons either soil themselves or figure out a way to try and use the chaos to their advantage.
• Manderly's fleet comes in handy for any evacuations.
• Davos finds Rickon and Osha and discovers a secret about Skagos and the people there.
• Dany gets four chapters where nothing happens.

Dream of Spring

• Readers discover the title is misleading, it's just people wishing things were better as they are attacked or starve to death during the Long Night.
• If the Boltons survive to this volume, they die during it.
• Arya returns to Westeros, but will anyone ever recognize her?
• Sandor vs. Gregor (hollow event for Sandor as his brother is now an empty shell)

Next Volume

• More people starving and freezing to death.
• Howland Reed and Bran are on what is now the Front Line near the Neck. Westeros has rallied what remains of their military commanders to try and halt the southward progress of the Others.
• Various characters reflect on how people like Ned Stark and Tywin Lannister would have come in handy if they were still alive.
• Randyll Tarly apologizes to Sam before riding into what will be his final battle.

Next Volume

• The Others push all the way to Dorne.
• Westerosi survivors flee to the Free Cities.
• Dany finally gets involved in the war effort.

Next Volume...