This kind of needs its own sticky.
Rune Horvik has clarified the new changes to the targeting rules. If anyone has any questions, let me know.
No cards will be errataed, though some will functionally change.
For example, the text on Decimate is:
Decimate
{G}
Sorcery
Destroy target artifact, target creature, target enchantment, and
target
land.
Because this is multiple instances of "target", the same permanent can
be chosen multiple times.
[Pre-CHK Targeting Rule]
409.1c If the spell or ability requires any targets, the player first
announces how many targets he or she will choose (if the spell or
ability has a variable number of targets), then announces the targets
themselves. A spell or ability can't be played unless the required
number of legal targets are chosen. The same target can't be chosen
multiple times.
[CHK Targeting Rule]
409.1c If the spell or ability requires any targets, the player first
announces how many targets he or she will choose (if the spell or
ability has a variable number of targets), then announces the targets
themselves. A spell or ability can't be played unless the required
number of legal targets are chosen. The same target can't be chosen
multiple times for any one instance of the word "target" on the spell
or ability. If the spell or ability uses the word "target" in multiple
places, the same object or player can be chosen once for each instance
of the word "target" (as long as it fits the targeting criteria).
Example: If an ability reads "Tap two target creatures," then the same
target can't be chosen twice; the ability requires two different legal
targets. An ability that reads "Destroy target artifact and target
land," however, can target the same artifact land twice because it uses
the word "target" in multiple places.
