The best idea Eugenides had was the viewpoint. It would be quite impossible to tell this story from within the Lisbon house, but by using anonymous watchers on the outside, the implausibilities in the plot fade away, and by just inserting carefully chosen details of their lives, the reader is automatically directed to fill in the rest by his own imagination, thereby fleshing out the characters. I can't say it works 100% for me, but then, I've never liked these kind of passive stories in which none of the characters seem to have any great ambitions in life, and certainly no inclinations of doing anything to attain them.