I think a card that just gives +1 card/+1 action on the next turn could give a good action reliability boost to the right type of engine and would be worth getting two of in a lot of cases. With one of these in play each turn, you don't need to draw a Village in your starting hand, and can have better reliability in a deck that doesn't have a ton of excess actions. Since you are playing this "Village" on the previous turn, it doesn't matter if your other one is the last card in your deck.
But it does matter if it isn't the last card in your deck because it's a stop card. The +1 Card and +1 Action you gain, you also lose when you have to play it.
[At the start of your next turn, +1 Card and +1 Action] is Ruins-bad. I mean it might be the strongest Ruins, but it's still in that ballpark.
but I get an extra card at the start of my turn, so I am no more likely to dud than I was without this card. If I have a deck that needs to over-buy draw to have reliability, this card potentially reduces the need to over-buy Villages also.
Yes, you are more likely to dud. And no, it doesn't reduce the need to overbuy Villages. This card (which I will call Layabout for convenience) makes your deck less reliable, not more.
You seem to be sort of tacitly assuming that you will always find Layabout at the bottom of your deck. But that's false, and it will be an anchor around your neck whenever you draw it earlier. Every time you draw a Layabout, you could have drawn something else, like a Village or Smithy variant. And that's not all: thanks to Layabout being a stop card, you will have lots of hands where you have the option between playing a Layabout and playing something better. If you play the better card, your Layabout was dead this shuffle, no better than a Ruined Village. If you play the Layabout, it only breaks even (about as good as a cantrip) but your other, better card is dead this shuffle.
I could maybe see a card that gave you an option. "Choose one: +1 Card and +1 Action; or at the start of your next turn, +1 Card and +1 Action." That might be worth $2. Layabout is garbage that clogs your deck only slightly less than a Ruins.