Honor of the Pure is a must for this deck also don't exspect Hero of Bladehold to drop too much. It is a really good card, with usefulness that will extend well beyond standard.

If you're keeping card:Norn's Annex for multiplayer purposes I'd suggest Ghostly Prison instead. Also Phyrexian Metamorph does well with Knight Exemplar

One of my first and favorite casual builds was and is a mono-white knight deck, so a lot of what I tell you will be based on my experience with The White Order.

Sigiled Paladin is not great because knights like swinging with a lot of powerful creatures. Giving one creature exalted does not make it all that useful or worth having in the deck.

Mentor of the Meek is kind of slow and ineffective given that many knights cost as much or less than it and will be getting buffed by Knight Exemplar .

card:Norn's Annex is not that necessary. If you can hit hard and fast it won't matter whether or not you have late-game defenses. I think you would do better to drop them for cards that cater to the aggro strengths of knights.

While Armored Ascension is good, Light from Within or even Honor of the Pure will usually be better since they apply the buff to your whole field. Armored Ascension still has applications and potential, though.

Celestial Mantle seems a bit slow. I think you'll probably be killing your opponent anyway by the time you could normally even cast it.

As a utility spell I think Holy Day is outclassed by Brave the Elements (which is far more versatile and suited to an aggro approach).

Your deck doesn't have much aerial presence. You might want to include Leonin Skyhunter s to address that problem.

Suggested changes:

• -1 Kinsbaile Cavalier
• -1 Mentor of the Meek
• -3 Sigiled Paladin
• -4 Holy Day
• -2 card:Norn's Annex
• -2 Celestial Mantle
• -1 Plains
• +4 Leonin Skyhunter
• +2 Knight of the White Orchid
• +4 Brave the Elements
• +4 Honor of the Pure /Light from Within

And yes Hero of Bladehold will see a price drop, creatures that are only beatsticks see price drops when there's a better option. Grave Titan is an example of this.

Perhaps Strata Scythe for deck thinning and to help keep you from getting twofered on Armored Ascension ? I like the Ascension but it attracts removal at remarkable speed. :P Nice deck!

Nice! +1 Really aggro and fun-looking. have you considered Elspeth, Knight-Errant ? might help, might not. Also, another fun card would be Coat of Arms because your creatures are so tribal.