Hearthpwn

Any worthwhile replacements for Prismatic Lens?

That's a tough one, I think I would go for second copies, starting with Acolyte of Pain maybe.

What's the 1 Elven Archer for?

You can use it by itself for removal, combo it with Equality, or with Bloodmage Thalnos and Acolyte of Pain for draw. It's cheap and makes your Crystology a bit more consistent (because you're increasing the pool).

It's not the best card in the deck but still useful. People already used it in OTK paladin before this expansion.

Edit: also, if you have Truesilver Champion equipped, you can do exactly 30 damage with Holy Wrath + Truesilver Champion + Elven Archer

Replacement for Crystalsmith Kangor ?

I would like to know as well

Zilliax maybe? idk, tough to replace since it also improves your Crystology

Why is Zephrys the Great in here? 

Your whole goal is to draw your deck then do your combo with holy wrath.Since you draw A LOT, you won't have duplicates in your deck after a while.Zephrys will be usefull in most of the situations :)