Obvs Cat got a raw deal from Walder Frey in AGOT, esp since he should have been at Riverrun anyway, but after his crowning it would have made sense for Robb to choose a Riverlands bride to cement his kingdom. With this aim in mind, how good a bride is a Frey?

goodqueenaly:

Honestly, while I understand the sentiment of wanting a union of Stark and riverlord to symbolize the union of the two kingdoms, I think that it’s just that, a nice sentiment without a real sense of necessity. After all, Robb is already in himself the union of North and Riverlands, as son of Eddard Stark and grandson of Hoster Tully; any child of his is going to carry the blood of both Great Houses. Moreover, there’s really no one Riverlands House that Robb “should” have been courting; the greatest Houses there are not dramatically stronger than House Frey (please correct me if I’m wrong, @racefortheironthrone)​,​ and no matter where he turns, 4,000 swords are not exactly going to revolutionize his independence campaign. What Robb really needed was someone who could bring a game-changing force to the table, a Margaery Tyrell or Arianne Martell; such a bride would not have been of the North or Trident, but in the choice between symbolic niceties or the continued independence of his realm, Robb would have been wiser to choose the latter. (Too, and relatedly, I think Robb has a little more leeway in his choice if his bride were someone who was already inclined to hate and oppose the Lannister regime; part of what made Jeyne Westerling such an unacceptable choice politically was not only her House’s relative poverty, but her father’s role as bannerman and soldier of the Lannisters.)

Again, I think it needs to be understood that Catelyn sold Robb’s hand cheaply, especially when Walder already wanted Edmure as a son-in-law. It’s a point I’ve talked about before, but it bears repeating. Well and good for Edmure, the Lord of Riverrun (he was not, strictly speaking, lord at the time of the negotiation, but you understand my meaning), to marry a daughter of one of his more important vassals – his own father did the same, and generations of Tullys before him doubtless did as well. As for King Robb, his marriage, incredibly important as it is, should directly further the survival of his dual kingdom. A Frey really doesn’t do that, nor any other riverlord House.

It’s iffy as to how powerful the Freys are within the Riverlands. I think the problem is that GRRM decided to give them 4,000 swords and then decided to give the Riverlands 20,000 swords and then didn’t realize that this would make the Freys an absolutely dominant orce in the land. 

Now I’ve made some estimates to try to figure out the Riverlands, but it’s a bit like trying to build a brick foundation on a cloud. 

But yes, agreed that House Frey’s 4,000 men were not the be all and end all of a rebellion that involved several tens of thousands of soldiers.