1. Roose
2. Balon
3. Garlan
4. Brienne
5. The Hound
6. Davos
7-11. Jaime/Obara/Greatjon/Darkstar/Randyll
12. Theon
Balon is frequently cited as the most overpowered card there is, but I think that takes for granted how Roose completely defines the entire Stark strategy and how/if you are able to attack them. Balon is especially beast-y when Greyjoy holds the blade, though, so if you wanted to give him the top spot I wouldn't argue too hard. The two of them and Doran are the only real contenders for the top spot overall, imo.
From there, there is a significant drop off to Brienne and Garlan, who are pretty evenly matched. Mostly though, I'll take swords over forts, and in particular a second sword can go a long way to keep whittling down your opponents forces. The Hound's second fort has that same effect in the inverse. Given Lanni's neighbors, he's as good as the Blackfish against any card but Mace.
I'll then put Davos over the masses of identical twins that fill out the rest. That his conditional strength kicks in right when you need it most (when you don't have your strongest card), is not dependent on other quirks of the battle or terrain (a la Mace/Victarion/Asha), and provides Bara with a badly needed extra sword makes up for the portion of the time when he functions as a medium card with no special abilities whatsoever.
Theon's ability has too many qualifiers to be all that useful. Give me a simple sword that works in every situation rather than extra strength that only works every second Tuesday.