The American Folk Festival will take over the Bangor waterfront again this weekend, 17 years after its first iteration helped convince people that the city’s waterfront was worth reviving and could even become a destination. While the festival is still a major draw to the waterfront each year the weekend before Labor Day weekend, the confab has gradually become a smaller version of itself, according to available tax documents and concert programs from recent years. Bangor is a different place from when the National Folk Festival first came to town in 2002, with an increasingly vibrant downtown area and multiple new entertainment options, such as the Cross Insurance Center and Hollywood Casino.