This deck is designed to be fairly balanced and still make Na'asiyah fun. the deck is really fairly simple: Eowyn quests, Denethor defends, Na'asiyah attacks.
Allies are there to boost questing power, bolster defense capabilities for the whole table and help make sure Na'asiyah has resources to power up.
At this point there's many ways to keep Na'asiyah stocked up with resources. Slapping Steward of Gondor on her is obviously the easiest way but it's pretty cheesy. The sideboard cards can help feed her resources from the real Steward if you want to keep away from the abuse of Steward of Gondor.
With a low starting threat of 22, the daggers should help Na'asiyah have a great base attack of 4-6 and her resources can give her the precise attack strength she needs to kill whatever she's up against. When dull set up with Firefoot, she can boost her attack really high, attack the weaker enemy and smash the second one with the splatter damage.
Denethor is a bit risky for a primary defender, but with a shield or two and the damage mitigation included, he should be able to cover until a couple allies are set up with the Raiment of War.
Weaknesses:
This deck uses up two popular/powerful heroes to actually make Na'asiyah work. Eowyn could be switched for Mablung if the rest is the table is covering questing.
With a low threat, it can be difficult to actually engage more than one enemy ina multiplayer context.
While able to defend several attacks, the Firefoot trick is basically the only way to kill off more than one enemy per turn.
Varients:
With such a low starting threat, its possible to actually get into secrecy and get the Resourceful generation going.
The "less cheesy" version would either put Steward on Denethor or leave it out entirely and use In the Service of the Steward on Na'asiyah to let Denethor send her resources.
Resourceful and Secret Vigil should be in the sideboard, bringing the deck to 50.