Chapel just doesn't seem to hit as hard most of the time when surrounded by all the expansion cards. Other cards do similar things without being so small. Forge for example would let you trash as many cards as you like and potentially get one back that you wanted (though you might also dislike that you MUST get something back). Also with Black Market in play you have no safety from attack cards, so Chapels just don't fare as well.
There are other ways to trash, and some of them are almost as good as Chapel if your goal is getting rid of Coppers, or something. As for Forge, I like the card, but it doesn't really compare to Chapel. You can always have a Chapel in your first two turns. You can't get a Forge until you have $7, which means you're also passing up a Gold
to get it (although, this is in an expansion that has Platinum, so it might not be such a big deal). You could probably have used your Chapel at least three times before buying a Forge. I think my favorite pseudo-Chapel is Steward. It can be used early in the game, and it has two other useful abilities to not make you hate seeing it in your hand later in the game.
On a related note, what are your experiences with Forge? It always looks so neat, but I've never had any real solid plays with it. I've used it in the past to prune out some Coppers or Curses (since they add nothing to the cost of what you get).
Saboteur could come out, but unlike many attack cards it gives nothing to its wielder, I never saw it as overpowered so much as unpleasant. As a card it's not a game-winner, it's just remarkably unfun to see in play.
It's power isn't in what you get; it's in what you take
from the other person. I mean, attack cards that also give you +2 cards or +$2 are nice too, but attacks are good in that they slow the other guy down. If your actions spent on attacking slow the other guy(s) down more than what you would have been sped up by buying an action or treasure, then it's a win on your part.
But, yeah, Saboteur is just plain unpleasant; far more than any other attack card, and it really changes the experience of the game. If I were used to playing "friendly" games of Dominion, I'd get pretty pissed the first time that was pulled on me.