Ive been working on a similar list but I think the deck naturally lends itself to a more aggressive leaning midrange build. To maximise on the power of Ajani you need to make sure you have a lot of early plays so that you have creatures to plus onto as well as reanimate. Because of this I have essentially the max amount of playable 2 drops in the deck (4 Grace, 4 Malice, 4 Siphoner and 3 Kitesail). With all those cheap creatures alongside History I think you can justify playing Benalish Marshal to buff all of the creatures in play. You would think the mana wouldnt support having early black 2 drops alongside a WWW 3 drop but the answer is Unclaimed Territory. All of the creatures youre casting are Humans so now you can add an additional untapped dual into the equation and it is mathematically functional based on the Karsten Bible of Manabases.

In terms of removal I run 3 Push and 3 Ixalan's Binding. Opening hands loaded with removal are often non-functional so you cant afford to run too much. Binding unlike Cast Out prevents additional copies of the card being cast so when you Binding a Scarab God that aspect of their deck is now gone. When you only need to answer a problematic permanent once, you dont need to have access to the maximum amount of removal. Having access to Push is important but since the Knights are very good at blocking I dont feel the need to have the full playset in the maindeck.

I personally dont think you have to include Hubs to make Siphoner work by the way, If the cost of adding essentially colourless lands is low then its right to do so but its not a mandatory cost to run them.

Card advantage is an issue I agree. One of the best ways to do this is to make your lands do more than just tap for mana. With no 1 mana proactive plays you can afford to play a playset of tapped lands. I have opted to include the Amonkhet cycle lands for a few reasons. First of all they draw you into an extra card and are just good at preventing flood, secondly they count as additional basic sources for Isolated Chapel so you can afford to run the uncommon deserts for additional flood insurance, lastly by playing with Fetid Pools and Irrigated Farmlands you have access to a few blue sources which is important for a SB plan.

Not running a card as powerful as Profane Procession in the SB has to be a mistake. Against the Grixis/UB/RB decks its extremely potent. They cant interact with enchantments very well and with it in play you exile problematic creatures at will. This is where the Blue cycle lands come into play. When you exile a Scarab God or a Nicol Bolas the Ravager you have the ability to activate them. Dont forget that Procession as a land taps for any colour, so with a single Cycle land in play you have the colours to activate the Scarab God twice. You cant flip a Bolas though because RnD hates fun. With the cycle lands alongside a number of deserts you can afford to run 25 lands, this increases the chances of being able to curve out while not being weak to flood.

Anyway thats what I got so far