I think the metagame is like a self-correcting marketplace. Everybody runs maesters, and so nobody runs attachments. Then all of a sudden out of the woodwork comes a deck with attachments that you can't deal with, so people start running attachment hate again, like maesters. Martell has really good cards, some are different, and some are just better. There is absolutely no doubt about it, and if you think otherwise your just wrong. Hell, their 1 gold refugee is a beast. and now a 1 gold three strength sand snake with intrigue and power icons with an ability? That isn't and ally or refugee or mercenary? There is no denying that is far to the right on the cost effectiveness scale (where the right is good). Think about how that character alone stacks up against the intrigue icons in Stark. Hell, think about how that stacks up against the military icons in Stark. Sure, you have Hodor (who is an ally and can't attack) and you have Hungry Mob (who is an ally and might kneel on you) or you have Knight of the Red Fork (who might kneel all your other cards or not even stand). So ya, sometimes they just get better cards. Unless there is a lot of Bastard hate in this lannister box (which would be flavourful, given tywins predisposition) your going to have a hard time telling me other houses get the same kind of love as Martell. Like look at their icon removal location that just came out. its boss. How many top notch stark cards have come out in the last two cycles? Well, we have Luwin and Meera. Harrenhal is a pretty good card too except it will die to all the location hate people are packing against Ghaston Grey. Thats what I thought. Don't get me wrong, I love to play Stark and I am not trying to *****. It is just that at the end of the day there are better and more efficient cards in other houses - particularly Martell. So pull your heads out of the sand (haha, get it?) for a second and accept the fact that God (Nate French... and Damon Stone) don't always give with both hands equally.
THIS BEING SAID
At the end of the day your only running 60-65 cards in a deck, so with all these options of good cards they can only fit so many in. And I think thats why we see such balance in terms of tournament results etc. All the other houses might have significantly fewer cost-effective/OP/competitive/whateveryouwanttocallit cards in absolute number, but things don't phase out. So you can still make a competitive deck in another house, it's just going to have less "competitive" options for what cards are worth those deck slots. For clarification: if you have 200 really good cards, you can still only have 60 in a deck. If you have 60 good cards, you can still only have 60 in a deck.
And if people want to complain about Lannister before it is here, remember this: hyper kneel is not coming back. It never left. Just ask Cersei Lannister. seewhatididthere?
@Kennon, I am planning on 3 GG, 3 Myrcella, 3 Edric, 2 RV, 1 Arianne (for actual challenges with RV and Arianne's effect). Use lost oasis, they will hate on GG more and you don't need to really worry about the GJ if your running Summer (with or without agenda) and have at least one Regroup (poisoned knife and the alchemist shop won't hold up against the tin link hate right now). Bounce the nobles to bounce their attachment laden/power heavy/high strength/stealthy characters, and use TRV with Lost Oasis like it was meant to be. Its French Vanilla, but it works. Plus those dupes of Myrcella and Edric you are drawing into can feed those Maesters of the Sun.