FAQ: Triple X different permanents are chosen at the same time. In other words, no permanent is chosen more than once.

"all cards"?

Presumably like all targets, it only applies to the valid things. So the ones in your hand :)

Feels surprisingly undewhelming. Both because it's direct-detroy which red disavours for creatures it can damage instead, and because it's 7-mana-and-some-extra-cards. For, admittedly, potentially a one-sided wrath. But so costly to use!

We already have the wording "discard your hand". And considering this set/user introduces a lot of new wording, how do I know that discard from the library is not valid?

discard my hand? do i chop it off first? left or right hand? can i substitute with fake hand?

If you want to play that way, you can go for the a bit more long-winded "Discard all the cards in your hand" that wouldn't usually be used on this card, but is entirely legit and clear.

With all the "discard a card" effects, were you ever confused and try to discard from your library?

technically "hand" is a zone. can you lose the zone forever if you "discard your hand"?

Discard means "To move a card from its owner's hand to that player's graveyard." Any reference to the hand is redundant.

My assumption is that if your use a wording different from the one that would usually be used (see Dangerous Wager) you have a reason.

If you use "discard your hand", I'm not worried about losing the zone, because I recognize the official wording and what it means.

Being fair; while it's standard mtg terminology, it's really not unusual for other card games to have you dicard from a deck, or even from in play areas.

QED "discard all cards" is the best choice of phrasing. It is the most accurate, least ambiguous (discard your hand?), most concise, most consistent (cf. discard a card, discard two cards, discard all cards.)

"official wording" is fallacy of appeal to authority. "official wording" that often changes and improves on previously "official" ambiguous, redundant, or inaccurate phrases.

moreover mentions of zones tend to be out of flavor. no longer add to mana pool, or shuffle one's library. they were removed due to the reasons mentioned above.

"Discard" only applies to objects in hand, just as much as "counter" only applies to objects in stack, "sacrifice" and "destroy" only apply to objects in battlefield, etc.

Actions that apply to objects in a zone do not apply to the zone itself (despite the wording); see rule 400.12.

However, I prefer to write "discard your hand" instead of "discard all cards", to be clear that it does not include opponent's hand; and rule 701.8 does not say that it doesn't include opponent's cards (which is strange, though, since "discard a card" is only your own cards, but that rule doesn't seem to say so, so maybe that rule is wrong).

So, the reference to the hand is redundant, but the wording doesn't look very well in this case if you do not mention "your hand". "Discard all cards" doesn't look very well to me (you aren't discarding all cards in the entire game, although that is not possible anyways).

now you invoke another fallacy. when an action doesn't mention a player, only the controller of an effect performs that action .

Gain 1 life. do all players gain 1 life? Draw a card. do all players draw a card?

are those phrases also confusing to you? seeing as they appear more often, do you often get confuse when you see cards with those phrases?

For that matter, if you're still confused, who performs the action for "discard your hand"? You say you are not sure which player "discard a card" refers to. But "discard your hand" is even worse, more confusing. Can an opponent discard your hand? for instance, "Target opponent discards your hand" may be possible?

Actions that apply to objects in a zone do not apply to the zone itself (despite the wording); see rule 400.12.

400.12. is mainly relevant for actions that do not imply or define an origin zone. Such as put, move, return, and exile. So these actions may directly refer to zones instead of merely objects in zones. Ex. "Exile all graveyards" makes sense, because definition of exile does not define an origin zone.

But where does "discard your hand" imply that this action refers to objects in hand? This phrase is direct contradiction to discard's definition. Therefore one may assume this phrase is meant to override the original definition of discard. See Golden Rule. Thus the finality of "discard your hand" can only mean moving the zone itself.

In fact, discard mentions two zones: the origin (hand) and destination (graveyard). So when you say "discard your hand", are you altering the origin zone, or the destination zone? Can one infer that you mean to say "put your hand into your hand?"

I edited my message above, since I am thinking better, now.

You are right about "discard", although the rule 701.8 doesn't mention that, which seems strange to me, since other rules (such as "ante") do mention that only the owner of an object can do that, and it seems clear that only the owner of a card is supposed to "discard a card", too, even though rule 701.8 doesn't seem to suggest that, somehow.

About rule 400.12, many actions apply only to objects and cannot be applied to a zone; this is what rule 400.12 applies to, I think, if it says to do that to a zone instead. The Golden Rule can't do something which is impossible by definition (the effect would have to change these definitions to make it possible, I think). A zone isn't an object, and can't be contained within another zone. (I do, however, think that it might be better if it said "objects" instead of "cards"; that would be clearer and better, in my opinion.)

"Discard" does imply an origin zone, but "discard your hand" just looks better to me than "discard all cards", even if both will work. (If you want to use "discard all cards" in this set, then OK.)