Abandoned Chapel: I think this card is problematic. First of all, it is significantly stronger than other existing Ruins. Trashing 2 cards from your hand is not an underpowered effect by any means. Compare to Trade Route, a 1 card thinner costing
that does nothing for you early on. But the main issue is, it's a solution for the other junky Ruins. If you so happen to have received an Abandoned Chapel via an opponent's Cultist, for instance, in a no trashing board, then you have a way out, whereas other players might not. You got lucky and gained the only trasher. Ruined Market has that problem too somewhat, what with it being the only +Buy in a given Kingdom. However, Ruined Market offers a nice minigame of fishing for it despite its opportunity cost. Plus, it is not as mandatory as what could be the only thinner in a game that offers junking and that's the beef I have with Abandoned Chapel.
Ruined Workshop: I like this! I'd toss Survivors out and slot in Ruined Workshop. Fits way more with the other Ruins thematically too. A poor gainer for sure, but y'know. All other Ruins are poor something. So this is pretty nifty.
Vacant Throne: I'm mostly meh on this. Collision problem of Throne Room buffed a notch. Which I guess makes it ok for a Ruins. I'd test it a bit to see how often, if ever, the effect gets used.
Ruined Village: Awwww... but I like the straight "+1 Action"... very thematic with the other Looters, minus Survivors. I agree that the current version of Ruined Village is the worst of the bunch, though.
Saboteur: I like the Attack. However, I'd consider making this cost
. Otherwise, well... I just imagine that one 4-player game where everyone opens Saboteur. Gotta lock it behind a higher price point for it to not get degenerate! If that's the case however, I'd buff up the vanilla bonus to +
. Less good in your engine than Torturer, but decent payload nonetheless. Just an idea!
Rebuild: This is almost strictly weaker than the aforementioned Replace. Usually, Ruins -> Curses. The difference is not much and in most games, it hardly matters, but it's there nonetheless. Thus, this is just a copy of Replace, but a weaker coat of paint. There would need to be a little extra something to balance it proper, imo
All in all, pretty good ideas! I do agree that Looters are too rare, even within Dark Ages. More Looters = more use of your 60 Ruins!