Yep, my first idea was the same, regular Village with bonus at $4.
But then i thought, why would I not play this? It draws me a card, which might be an Action. Besides when drawn dead, my suggested version is good to topdeck from hand if you don't need the extra Action, Coin and Buy this turn.
Maybe you don't want to do it by choice because if you don't play it immediately, it slows down the deck a bit.
If it went to your hand instead, it would be more interesting. Although maybe then it's broken, dunno.
Okay, this would be the Tunnel version of it:
Underground Village (Action - Reaction) $4
+1 Card
+2 Actions
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When you discard this, you may reveal it and put it into your hand.
Very strong with sifters, but Fortress is even better with trashers.
I miss the draw dead ability though.