WFL didn't really set a standard IMO... it lasted a long time at the top of the charts but it's not really that memorable because it's so basic and repetitive... so it has already been surpassed IMO.
Yes. A lot of songs have been bigger than WFL and will be. It didn't start a trend only followed. And Diamonds seems bigger than it, maybe because she releases annually.
This song is so overrated, nothin special about it, just a song which followed the trend of songs with breakdown like Party Rock Anthem, Sexy And I Know It and The Time.