Why weren't they done this way:
Alternate Feast:
Trash this.
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When you trash this, gain a card costing up to $5
Maybe it makes feast a bit too powerful if you can "play" it using a trasher, so why not separate effects. For example;
Alternate Embargo:
+$2
Trash this.
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When you trash this, place an embargo token on a supply pile of your choice. When a player buys a card, he gains a curse per embargo token on that pile.
It could even add an interesting "reaction" dimension.
Alternate Pillage:
Gain 2 spoils, trash this.
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When you trash this, each player with 5 or more cards in his hand reveals his hand and discards a card that you choose.
I hope they take this approach with future oneshots.