Well, I mostly concur with BryndenBFish here. Roose has played his hand conservatively and smartly – turfing out the Ironborn from Moat Cailin to give himself Northern nationalist cred, building a base of supporters (albeit of uncertain loyalty), planting traitors in Stannis’ camp, and using the winter to his advantage. 

My one critique would be that I think Roose has played a touch too conservatively. A small contingent of cavalry sent out to harass scouts and foragers, cut trees down across the pass, attack the supply wagons, etc. could have dramatically increased the pressure on Stannis’ force without risking much. As it is, Stannis was able to make the march largely intact albeit low on food, Something of a mistake there. 

Also, I think Roose’s making something of an error in his response to the news that Stannis is less than 3 days away. Sending out the Freys and Manderlys has a number of political and logistical advantages, but it means that he looses the advantage of numbers on the battlefield – he’s sending ~2,300 men to fight ~5,400. Roose is probably hoping to whittle Stannis’ army down piece by piece while holding the core of his forces in reserve (and using the Karstarks as his psychological ace in the hole), but what he’s risking is that, if the Battle of Ice ends up as a (non-Pyrrhic) victory for Stannis, his core will be facing an army of equal size and superior morale. 

Good question. To begin with, the Tyrells don’t really have a dog in the fight and are likely to hold back and try to play kingmaker with the various claimants. 

Tommen, as a mere child, a half-Lannister, and a rumored half-Lannister, would get no support from the Stormlands. Chances are, when Stannis raises his banners, a good chunk of the Stormlands rise with him. Not all of them, hell not all of them rose for Renly, but a good deal of them.

Basically, Stannis would have been able to get a roughly equivalent size army to the one he got in ACOK much faster, and chances are would not have had to worry about the Tyrells slamming into his flank at Blackwater – while the Lannisters might have tried to make a deal with Mace for Margaery’s hand, the armies of the south not being mobilized and certainly not being mobilized that close to King’s Landing would have made their arrival come much much later than OTL.

So most likely the Battle of Blackwater would have happened weeks earlier, without the boom chain. Stannis’ navy would have taken a good deal of damage, but he would have been able to cross with Salladhor Saan’s ships and force his way into the city with his army largely intact. 

I like Sam a lot, but I think he’d be a terrible Lord Commander, lacking in self-confidence and unlikely to have the respect of his men, despite the whole Slayer bit. Shoving a very good adviser out in front isn’t a good idea. 

He doesn’t seem to have been a very active Master at all – definitely someone more involved in the Small Council than his own department. Seems to have preferred pointing out the mistakes and shortcomings of others rather than pushing a positive agenda. 

Well, historically the role that the maesters play in Westeros was played by the Catholic Church in Medieval Europe. While priests were rarely as comprehensively educated as the maesters, they were the one (mostly) literate class in Europe, and the original universities of Europe were established to train them, and priests were often attached to noble households to provide advice, religious education, etc. 

The Master of Laws position is a royal appointment, so that would be up to the King.

As Lord of Storm’s End, I think that would also revert to Robert, who could choose to keep it, give it to one of his kids, or give it to Stannis.

In general, start from what’s likely to have been in GRRM’s research base. Which has tended to be very Euro-centric. 

Not really. The early stages of the Faith’s growth is pretty close to the rise of Christianity, albeit one more reliant on the Arian Goths and without a Constantinian establishment. 

But historically speaking, the parts of Europe that remained pagan were either missionaried into Christendom or brutally crusaded against – we think of Crusades as entirely focused on the Middle East, but Charlesmagne’s Saxon Wars and his campaigns against the Avars and Slavs set the pattern for the Wendish Crusade, the Livonian Crusade, the Estonian Crusade, the Prussian Crusade, etc. 

Essos is heavily involved in the slave trade and is also Westeros’ major trading partner. Most likely you’d see increased prices for Essosi exports to compensate for the loss of slave-based revenues. 

And of course, a lot of mercenaries who might have been hired to fight in Westeros ended up going to fight in Meereen.

See here.