Could maybe run a 20th land (or 5th mana creature), first cut would be giver of Ruins. SB was whipped up before WOTC took a jackhammer ot the format, adjust as necessary (Turn Kataki into another Knight of Autumn at minimum). A mono-white soul sisters build could be generated, but that would be more of a deck building exercise, the green splash is "free" because we want to play the horizon canopies anyway.