Just because a card does everything and more (or less) than another card, the price point shouldn't automatically moves up or down one coin.
Consider the following three cards:
Village
Action $3
+1 Card; +2 actions
Lightly-Walled Village
Action $?
+1 Card; +2 actions
At the start of Clean-up, if you have this and no more than one other Action card in play, you may gain a Curse. If you do, you may put this on top of your deck.
Walled Village
Action $4
+1 Card; +2 Actions
At the start of Clean-up, if you have this and no more than one other Action card in play, you may put this on top of your deck.
Taking a Curse is a cost in all but a few edge cases, so Lightly-Walled Village should cost $3, even though, because it gives you a choice, it's strictly better than Village. I was being facetious earlier then I said Walled Village is strictly better than Secluded Township. Still, gaining a Curse is almost always bad, and you're likely to topdeck a Walled Village more often than Secluded Township. I'm confident Walled Village is better, and Walled Village is a weak 4.
Personally, if Secluded Township and Village were both out, I'd probably buy both. I don't think I'd topdeck it without a good trasher though.