I think swindler is terrifying for a Mint/FG player. It's true that in the first shuffle you have a 50% chance of them hitting an estate. But if they hit your mint, fg, or copper (in that order of badness) you're pretty sad: with such a small deck the effect of the dead card they introduce is gonna be pretty big. I think it maybe would've been an even stronger attack to get two swindlers, and ignore familiar.