The object of the main game is to defeat a series of enemy duelists in order to acquire the Red and White Rose Cards, which hold the key to ultimate power, or something of equally great importance
What does Impact Tremors do
What is the real reason that prompted me to undertake it
However, that was just reprinting six cards, and there are hundreds of new cards in the 40k commander decks - not to mention that the Astartes, Necron and Tyranid creature types are part of Games Workshop's intellectual property, so presumably can't be reused without their license.
Yawgmoth's Will can be an absolute terror when played right, especially since it exists in the color that cares most about the graveyard
For all things sticker-related, check out Rosewaters post on his Blogatog