Permafrost
x3
2
Crownwatch Paladin
x4
2
Dusk Raider
x4
2
Linebreaker's Shield
x3
2
Vanquish
x4
2
Vanquisher's Blade
x4
3
Jennev Merchant
x4
3
Kosul Battlemage
x4
3
Mirror Image
x3
3
Unseen Commando
x4
3
Valkyrie Enforcer
x4
4
Auric Runehammer
x2
4
Sheriff Marley
x4
Justice Sigil
x8
Primal Sigil
x5
Crest of Order
x4
Crownwatch Standard
x4
Hooru Banner
x3
Seat of Order
x4
View Deck on Shiftstoned
i think playing marketed mana might be a bit of a mistake. it seems to be consensus among top players that market spots are invaluable and one really aught to just build a better mana base. for example, none of the decks in the top 16 of the ETS invitational played marketed mana, not even the super value mid-range types.
currently you're running 28 in the maindeck but i'd like to point your attention to a particular list, Kang's AP Mid.
Kang has brought this same list (well, with green merchants) to the ETS for the last several weeks and I imagine it to be rather tuned for this particular curve. i also think it's rather similarly structured to your current deck, especially if you consider Linebreaker's Shield to be 5 drops. Kang runs 26 raw power and 4 psuedo power in the form of Vara's Choice. i think your current list is in an interesting position in that it is so heavily Justice favored that you might be able to run a couple Lingering Influence for your psuedo power, but otherwise you might just want 4x Seek Power. for cuts, you might consider just removing 2x Auric Runehammer and converting 2 normal sigils.
as far as what to play in the market, there's plenty of stellar options at the moment:
my first thought was Unseal, but that's way less relevant in a deck of aegis dorks. Vision of Austerity is a staple but i rarely find myself using it outside of punishing mask decks. Thunderstrike Dragon is also one that recently came on my radar, especially if you're playing Dusk Raider. although i think that's geared towards more midrangey-midrange like Good Hooru. Clan Standard/Eilyn's Choice are also considerations.
but i wonder if Crystallize/Entangling Vines might be the way to go?
since you're trying to be more aggressive and playing Kosul Battlemage over Jotun Feast-Caller, it might give you the opening you need to jam in on the ground in a world of deadly units and tokens.
I guess you are right in your assessment of why market power is a worse option than running more situational cards and more power in the main deck. Considering what market cards to run, I've come up with many different potential slots too: Vision of Austerity is good against Cookbook and Mask and sometimes against Xenan Obelisk. Unseal is protection against removal or board wipes (Vira on 4, Harsh rule on 5) and against Scream. Eilyn's Choice can be similar to Unseal and also be used on units that are already in play and can offer more answers against fatties. Entangling Vines as an additional way to bypass enemies. I also thought about changing the Jump Kick for a Changeestik; The unit keeps the +1/1 buff and the flying ability at 1 more cost and the card can also be used later on as pseudo hard removal on an annoying unit. I also thought about using Shelterwing Rider in the market as it offers a good unit on curve, is good at blocking, difficult to fully remove and it wears weapons very well. I can imagine a 2/7 endurance multifaction flying unit to be quite annoying to deal with. Bring Down could be used against the unit that gets screamed back (silence + removal in one) or against Rizahn. Gift of Battle is another option to get more damage in. Eilyn's Intervention could be used against some narrow spells like Slay or Wisdom of Elders and it can also deal with units that get screamed back but I think it might be too specific to be worth 1 out of 5 market slots. Substitute could be used as a pseudo hard removal too e.g. on say a Vara or a SST. I have also seen a Feln Aggro deck run Torrential Downpour to kill tokens, pop aegis, scout and deal 1 damage face (which sometimes matters a lot). Poaching drake is also an option.
I think Permafrost, Linebreaker's Shield and Mirror Image are already set as they offer a very lot of value and flexibility. I think I will follow your advice and add 3 Seek Power and 1 Lingering Influence and try market Thunderstrike Dragon again (used to run it in a more midrangey deck but I did not have a lot of success with it so switched to this aggro style deck). Maybe the Dragon is like Unseal a way to play around removals but instead of countering removal, it offers 2 nice units. I think I'll also go for Entangling Vines, as this provides a very valuable way to gain Tempo to win the damage race when both player's resources are exhausted and there are only a couple of units on board; also, unlike Permafrost, it can't be countered by Bore (Bore on Permafrost on e.g. a Vira is how I lose sometimes because of the board and HP swing they gain).
I can see it doing well against most control decks though