I do not have that much experience in building decks in standard format so I ask you:

Are decks built around a certain trait like king/queen or Dothraki just flavourful or can they be actually quite strong? What is your experience using or facing them?

Well some traits are featured by a whole theme that´s worked around. If you want trait theme decks that are also good to play, it´s best to start with Tyrell , Bolton, Arryn and Asshai .

Dothraki is at the moment not very playable, Clansmen are too few, same is true for most of the traits associated with the houses Martell and Greyjoy. Tully is great if you play legacy and even better if you play Legacy without the highlander rule. Brotherhood has not enough good charachters and no support, there are too few kingsguard charachters. Nightwatch and wilding is great if you are playing with the WED block. Knights were great in VED time.

So it depends, some traits (and factions) rotate in- and out of the current play formats. ~Oh, and dont try an ally deck. ;-)

The problem is that at the moment there aren´t that many cards that feature already existing traits, most of the older traits just feel like they are unloaded flavour content on the card.

In Standard, they can be quite strong and competitive - depending on the trait and the build. When VED and WED were in the environment, Night's Watch decks were fairly common and reliable. The loss of WED hit the Night's Watch pretty hard. Last April, I had a deck built around Kings and Queens that gave people fits (the current incarnation still does in Standard...).

In LCG, Old Ben is right - the quantity and development of synergistic trait-based cards is still catching up. A lot of them make good sub-themes in LCG, though (Baratheon can still do a pretty good LCG-Asshai deck, at least as an undercurrent).

There are some cards that make you believe there could be some synergy like Kennel Master, Feral Pack and Winterfell Kennels. On the other hand it seems like you would end up with a lot of cards with Military icon only...

I think it would be nice if you were more rewarded playing a certain faction or a pure House deck. The only card I know that does this is Bear Island and only because locations are pretty save in LCG. In standard you could add Grey Wind making a Stark creature/direwolf deck but I fear it won't be that competitive.

Any more positive examples for working flavourful standard decks? A War crest deck?

mischraum.de said:

War-crest decks are very competitive. Try it out of Stark or Lannister with a special eye toward the House Bolton trait. There are enough events keying off of the crest, which appears on characters with all 3 icons (though military and power are the most common) that it can be both balanced and brutal. And remember that with the Boltons, both ALPHD and They Live! can work, no matter what the House card happens to be.

With reprints of Poison and Grand Maester's chain in the Legacy Pack, and the addition of Maester of War from Clash of Arms, a Maester deck could be viable, particularly in Martell where you'll have more options (through icon manipulation) to make up for their lack of military icons. Maesters will also open you up for a Learned crest sub-theme.

A flavorfull deck concept that worked at all times in standard was the Intrigue focused Lannister. It´s not flavorfull concerning traits, but it fits the books very nicely if you have Cercei, Varys and such intriguing around and triggering a vast amount of nasty effects by doing so.