I can only imagine the apologetic dialogue each turn, "Sorry, Spike, but Ursine Monstrosity chose to attack you this time
Death Toll is good, but as is often the case with these preconstructed decks, it's not perfect
Invitations will go out via email, and the lucky few (thousand) will have a 72-hour window to purchase the cards
Millstone would have a huge impact on one other Magic player
The unfortunate part here is Journey into Nyx rotates in October, so if you're interested in Standard, the longevity of the cards in that particular pack is questionable
They'll literally never go away, and will only get better and expand into new design space as Magic continues to grow