My current submission: a sort of "Stockpile/innovation" variant.
Ie, it gives you the powerful benefit of being able to play a card you get NOW, but with the cost of exiling itself. Similar to Stockpile, if you can somehow get back your Quickdeal, you could get a lot of extra coin that way as well.
A couple of things: "Exile" should be capitalized (see
Sanctuary). Also, "you may Exile this to set it aside. If you do, play it." is confusing in this context. When I first read it I thought "it" referred to Quickdeal, which got Exiled, then set aside, then played. I think default reading of "it" is the thing you are currently talking about, in this case "this" or Quickdeal. I would suggest "...when you gain a card, you may Exile this to set that card aside. If you do, play it."
The "it"s seem to be multiplying. I can work through what you're doing, but as the card's wording is now I think it would trash copies of Wooden Spikes, not the card you gained. You might try "...to reveal your hand and trash all revealed copies of that card."
You also might consider taking out the "you may first" language, which I don't think is necessary for the card to work (see
Falconer), and without it can be used to trash cards you gain to your hand, either from a Torturer attack or using Sleigh.
Brazier (Action, $5)
+3 Cards
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While this is in play, when you finish playing an Action and it's still in play,
you may trash it for +1VP.
Turn your Action cards into VP tokens once you're done with them. You can even self-immolate if you want. Of course, you need extra actions if you want to trash other Action cards...
Here, again, I think the "it's" is hard to understand from the card's text. I know from your comments that "it" refers to the Action card just played, but because you earlier talked about Brazier being in play, one might think that "it" is Brazier. You might try "While this is in play, directly after you finish playing an Action card, if that Action card is still in play, you may trash that Action card for +1VP." (See
Royal Carriage).