1) Olenna Tyrell - She just killed the king and has Littlefinger as an ally. Tywin wouldn't last a month if she pulled her support. Now she just has to have her smoking hot granddaughter take Tommen's cherry and she will be the de facto ruler of the 7 kingdoms. Seems like the odds are in her favor.
2) Tywin - he has made a lot of deals with a lot of devils. Roose Bolton and Walder Frey are more liability than asset as allies. Tried to make friends with the Martells, but that ended up with Oberyn getting his skull crushed as the Mountain confessed to raping Oberyn's sister and killing her children, so he can probably cross the Martell's off his Xmas card list. His children all hate him, and he is about to make the only competent one of them a head shorter.
3) Littlefinger - He has the Vale, he has Sansa, and he has a very powerful ally in the Queen of Thorns.
4) Stannis - the Iron Bank is a good friend to have.
5) Khaleesi - the dragons don't listen to her, and she is turning out to be kind of a screw up as a ruler.
6) Mance - I would like to control an army of giants and mammoths. That would be pretty cool. Unfortunately, he is on the wrong side of the Wall right now.
7) Cersei - mostly a screw up but she is still mom of the king and she has managed to get her little brother scheduled for execution.
8) Tommen - a lot more focused on what is inside of Margaery's dress than ruling.
9) Sansa - just became a player.
10) Martells - they are probably pretty pissed off right now.
11) Roose Bolton - probably the smartest player in the game, but he just doesn't have the cards to win. He knows that as soon as a Stark shows up, his support evaporates, but in the meantime, he has a wilding army about to bust through the Wall and come hurtling down on him. Nobody thinks he is going to win or even hold the North.
12) Balon Greyjoy - idiot
13) Bran - on suicide mission to fight the ice zombies. That should take him out of contention.
14) Tullys - So Kaitlyn takes Tyrion prisoner and effectively ends her family as a major player in Westeros. That is what blowing it looks like.
Not independent players:
Margaery - still on the QoT's team.
Davos
Jaime - not trying
Brienne
Jorah
Arya
Final Season 4 Rankings (ranking overall team, not just person)
1) Olenna - in the driver's seat now. Cersei is dependent on the Tyrells more than Tywin was, and Margaery is still smoking hot and working on getting in Tommen's pants. She has one of the best knights in the kingdom on her team in Loras, but her son is a doofus.
2) Littlefinger - His most dangerous adversary is gone now, he still has the Vale and Sansa, and he just has to figure out a way to get rid of that twisted little wretch Robin and he will be in very good shape.
3) Stannis - good tactical move by Stannis. Mance and Stannis should be natural allies because Mance and the Red Witch are more afraid of the White Walkers than anyone else. Davos and Red Witch are a good sidekicks, although his wife is a drag.
4) Cersei - she was pretty gangster in the last episode, telling off her dad and then banging Jaime in the kingsguard room. She controls the Lannister armies and the king now, but pretty much everyone hates her and she is kind of a screwup when you review her body of work to date. As for her entourage, Jaime is erratic and untrustworthy, Pycelle is an idiot, but Qyburn is badass, and definitely the kind of guy you want on your side. With Tywin gone, I will put Tommen on her team, for now.
5) Danearys - She seems to call every coin flip the wrong way, and her advisers are pretty much useless now that Jorah is gone. Selmy, Grey Worm and Missandre are just not cutting it, and she inexplicably started banging Daario. One dragon is getting a taste for human flesh, and the other two are locked up in a cave. Hard to pick her to win at this point.
6) Sansa - On Littlefinger's team for now, but an increasingly powerful player in her own right. She also has a cold-blooded killer for a sister should they ever meet up again. If Hubie Brown was doing a GoT draft, he would be raving about Arya's "upside". Tentatively putting Brienne on Sansa's team for now, and Brienne did some nice work on the Hound.
7) Doran Martell (we will meet him next year) - Tywin was the only thing keeping this crew in line. Oberyn's dead and the Mountain publicly confessed to some awful stuff against the Martells. Cersei has a problem here.
8) Balon Greyjoy - still an idiot.
9) Bran - The Tree Guy is a good ally to have, but I don't know how Bran gets out of that cave with the skeleton creatures from the Mummy right outside the entrance. Jojen seemed to be the only smart one on his crew.
10) Roose Bolton - Add Stannis to the list of Bolton's problems. Ramsey could use some sensitivity training too.
11) Walder Frey - people are really, really pissed off at him. He is still in the game though.
12) Mance - He had a 100,000 man army, but unfortunately they were Wildings and pretty much uncontrollable. He is not in a good spot right now. Ygritte, red beard guy, and the crazy baldhead Thenn were the only members of his crew worth anything, and 2 are dead and 1 is in chains.
13) Tyrion - he is free, but in a box on a ship that could be going anywhere.
14) Varys - The guy Varys sets free happens to kill the most powerful man in the world on his way out the door. Oops.
Out of the game (Leaders only):
Ned Stark - idiot.
Kaitlyn Stark - idiot. Don't start a fight you can't finish.
Robb Stark - idiot. Did he have to marry her?
Renly - nobody saw that coming. I mean, who expects a demon monster to crawl out from between a witch's legs and kill the leader in the War of the Five Kings with the most badass lady knight in the world standing right there doing nothing?
Tully's - Siblings: Edmure is a doofus, Kaitlyn is an idiot and Lysa is batspit crazy. Probably best for that bloodline to end.
Joffrey - surprised it took so long.
Robert Baratheon - booze and boars don't mix.
Oberyn - No one turned a great victory into literally a crushing defeat quicker than this guy.