These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Applicability: The movie works because it doesn't matter if you are not Greek, every family has a series of quirks that make it hard for outsiders to get on the inside. You can include almost any number of variations of ethnicity and religion into the title and the movie largely comes out the same.
Family-Unfriendly Aesop: The unwanted fuss over Toula's wedding can come off as "What your groom or you wants in the wedding doesn't matter, so feel free to change anything and everything about it to suit your family." However, it's also often Truth in Television.
Hollywood Homely: Partly averted in that, while certainly attractive, Nia Vardalos is anything but "Hollywood beautiful," and her "homely" look was genuinely convincing.
Roger Ebert: Everyone in this movie looks like they could be a real person. The romance involves not impossibly attractive people, but a 30-year-old woman who looks OK when she pulls herself out of her Frump Phase...I relaxed, knowing it was set in the real world, and not in the Hollywood alternative universe where Julia Robertscan't get a date.