I didn't say the new wording clones the effect. I said it "maintains what appears to be the intent," which is to destroy a permanent that just came into play. The reason I referred to it as a "retroactive Counterspell" is that most of the time, players only play one permanent per turn. In much the same way, Counterspell usually only has one legal target, but sometimes has more than one (particulary during counter-wars).
Imagine the Blastoderm example. Player A plays a turn 3 Blastoderm, and player A subsequently plays <This Card>. Whichever version you use, the effect is the same.
So the effect would usually be the same, though I did acknowledge that there were times where the uses of the two versions could differ. Anytime a player plays more than one permanent in a turn would be one such instance.
So I agree that your wording more closely mimics the original, but since
Zadok wanted to know if his version is too good -- and it is, for reasons that go beyond the card itself -- I suggested what I felt was a better wording. better for the card, and better for the game.
My main issue with the card (the land-kill possibilities being a strong secondary) was that it avoided targetting restrictions. My revision hardly weakens the card (Diabolic Edict is generally recognized as a great card, for example) it just avoids what is, in my opinion, a Great and Terrible Evil
that being ignoring untargetability.
As far as the land-kill thing goes, even if your deck isn't all land-kill, this card is great (with either wording). Say you're going first and play a Swamp. Opponent plays Plains. You play Mountain. Opponent plays a Plains, then White Knight, and passes priority with White Knight on the stack. Now you have a choice: play <This Card> now, and the opponent loses her new Plains, or wait until White Knight resolves and she gets to choose which she loses (or you do, going by the original, more powerful, wording). Either way, you're way ahead of the game. On your turn, untap and Stone Rain the remaining Plains. Your opponent's best-case scenario here is either she's left with a White Knight and no land versus your 3 land, or one Plains (and no Knight) versus your 3 land. You have an incredible tempo advantage, even though your poor opponent is playing with efficient creatures.
Slower decks, and decks light on permanent-creating spells, would find having their land blown up this way rather demoralizing, don't you think? And yes, I'm saying that the example deck runs only 4 Stone Rain as dedicated land destruction, with this very efficient and versatile card taking the slot that Pillage might have occupied. This leaves plenty of room for lots of other nasty stuff in red-black.
Anticipating counter-arguments involving playing against green decks with alternate mana sources... I Shock or Seal your 1st-turn mana-monster, and next turn you're in the same boat as your unfortunate white-playing opponent was earlier, with no significant loss of card parity.
So I reiterate that the hypothetical card, as posted, is much too strong, conceding that even my revision is nearly as powerful, and recommend not only a change in wording, but an increase in cost or at the very least a clause to prevent its affecting lands.
In short, to answer
Zadok's original question, "Yes, it's too good.
