I'm sorry i have to say this, but no. I don't want the event to be witty or requiring clever play. I don't want you to lose an additional $1, or have to decide between buying it or another card. I want it to be straightforward, in your face, no shennanigans, "you can trash a card per turn for free". And it will stay like this until i play it. And if i find that's no fun, well, i guess it wasn't a good idea.
We have trashers that cost something. Every trasher costs something. I want free trashing. We don't have free trashing yet. And trashing dominates. Junking dominates. Can you ever skip Witch? No, you can't. Can you ever skip Chapel? No, you can't. (I know this isn't actually true). Donald X himself has stated once that he wasn't aware how extremely strong cursing and trashing are, and that he might have thought about ways to "remedy" that if he had noticed in time. Well, we all know that Dominion is the way it is, and trashing and cursing just are that important.
The event is the attempt to open up another world of Dominion. Not to replace the old one, heavens no. Blessing won't be in many games. But when it's there, i want Dominion to be a game where you can a bit more often consider skipping Witch. A world where you can consider skipping Chapel. And i don't want this world to be available to only those that produce excess money, or those with excess cards, or those with excess buys. I want it for everyone.
If somebody plays a game with Blessing and says, "man, that's genuinely unfun", i'm all ears. But if the worst you can say is "Well, it played really different", then cool, because that's what it's about. Nobody minds Chapel being just "trash up to 4 cards". It's not "discard X, trash Y". Chapel isn't interesting. The games Chapel creates are.
I have made it "once per turn" to make sure neither trashing nor junking become really useless. You can still trash faster with Junk Dealer. You can still keep somebody busy using his Blessings for your Curses. But it's a different game now, and you don't have to "pull something off" to have that. That's how i want it. No "pulling it off".
I know i'm a lame guy who orders his pizza with just salami, even if he could have had additional ham for free. When i want a chocolate muffin and somebody puts sprinkles on it, i say "I would have mentioned if i had wanted sprinkles". If i want an event that trashes a card per turn for free, then that's what i want. I will gladly offer everybody the template to do their own version if they prefer it different. But this is my version. Let me have it without sprinkles.
Edit: Also, i really don't want to hurt anyone's feelings with this. But please try it out as is, or give me the time to do that, before changing it to be more clever. Please.