Some very disjointed thoughts:
You could really up your power level by splashing green for Knight of the Reliquary and Wilt-Leaf Leige. This also gives you access to sweet stuff like Horizon Canopy, Stirring Wildwood, and Rancor, but obviously the manabase gets really expensive.
Don't run Day of Judgement; that's so far away from what you want to be doing. You just want spot removal in the form of Path to Exile. I'd even go so far as to put the O-Rings in the side.
I think a key piece of tech you're missing is Brave the Elements.
Also, if you've got it, a singleton Elspeth, Knight-Errant could be backbreaking.
Kinsbaile Cavalier seems nuts as a one-of as well.
Sideboard needs Thalia. Maybe Leyline of Sanctity as well? You also need Stony Silence. If you're not running Knight of the Reliquary, you should consider Rest in Peace as well.
I will consider splashing green. But it worries me.
I like Day of Judgement if the game goes late, or alternatively, to clear the way for knights. Obviously, given the deck I don't want the game to go late. But, having 2 exemplar's on the board makes me not care if I board wipe. Actually, DoJ is a holdover. At one time I was considering running Knight of the Holy Nimbus. DoJ would let them regenerate. I've since pulled out Knight of the Holy Nimbus, so I should switch to Wrath of God. Emeria, is also in there for late game to pull creatures out of the graveyard if need be.
Bave the Elements: Yes bolts and path's are always of concern, that would indeed help.
Elspeth is a possibility.
I go back and forth on Kinsbaile Cavalier, (very useful) but Hero of Bladehold seems to put in more work particularly with honor of the pure on the board. Not sure, I may side in kinsbaile cavalier.
Stony Silence: Yeah sounds good.
Rest in peace: Is already in sideboard.
Considering running a couple Ghost Quarter's, basically a strip mine.