Random Generator gave me Shielding Plax and Plains, shifting the plax to white. That's simple enough. Looking at what's needed in the set, I find... that all the white common and uncommon slots are filled. This needs to be a Rare or Mythic white Shielding Plax.

Fair enough. I'm pretty sure someone's going to come after me for putting card drawing in White... but I figure that the color of Reparations and Armistice can hack this at Mythic, as long as it's a very rare event. The idea is you did something for your opponent, and you expect something in return, hence the Orzhov reference. If it really bothers you, at least you can't target a player with a second Palladium Plax until the first one is destroyed.

Personally, I'm not really sure if the cost is fair. Mostly, I kind of hand-waved the cost away with "Well, it's Mythic. I can't make it a bad card.") I'm pretty sure few people would want to cast Ivory Mask at six, and this isn't very enticing if it only drew you 2 cards... I don't know. Maybe this is one of those cards where increasing the white in the cost is justified.

It's a sneaky "Sideboard me" card against players who want to enchant themselves, or gain life or similar. Also fun in "Not really my opponent, are you?" formats. and the downside white doesn't care about much. AND you can use it to completely win against creatureless decks... Yeah, this is mythic.

Doubt I'd ever use it, mind you.

Or targeted card draw, which is probably the most powerful "target me" spells. It seems to vary a lot whether the best card draw is targeted or not.

I forgot about targeted card draw. I guess that's a reason alone to have this card draw you only 2 cards when you cast it. I'm still mulling on that.