The idea that there is one moment in time,
upon which everything that comes after turns,
and which single-handedly makes or remakes the
universe, is a popular one. I'm not sure how
much that works in real life, but for now it
only matters that it works in fantasy settings.
Perhaps this card symbolizes Sarkhan's ability
to choose whether Tarkir's (new) present will be
dominated by dragons or by humanoids?
Metaphysics and storyline issues aside, I don't
think black has had quite as straightforward an
effect like this since Damnation. You guys
already know how to play with Damnation, and one
that can be one-sided with the right creatures
in your deck is even scarier.
Today's card of the day is Crux of Fate which
is a five mana Black sorcery that has a choice
of either destroying all dragons or all
non-dragons. For one mana more than a
Damnation this does allow designing around it to
be one-sided, plus is allowed in Standard. Those
two factors alone will get this play and
possibly some offbeat decks designed around it
as a finisher.
In Limited this is a board sweeper that can
leave creatures on your side of the field with a
fortunate draft pool and is far too much of a
risk to pass in Booster unless absolutely
necessary. In Sealed it is a very powerful
incentive to build around black, particularly
with any dragons available as a possible (if
somewhat unlikely) game-ending combination.
Anything that basically reads "Destroy all
creatures" is going to be powerful and have its
place in decks. Anything that basically says
"Destroy all creatures EXCEPT something you
control" has the potential to be huge. There
will be times when an opponent has dragon
creatures and non-dragon creatures at the same
time, making this only a selective kill spell,
but if you build your deck right, you can make
this happen for you more often than it helps
your opponent.
One of these days I want to activate my
Mutavault in response to someone playing this to
destroy all non-dragons and say "Ha! Mutavault
is a dragon! It scoffs at your board wipe!"