Development Hell: While the series itself didn't suffer this, Fan Sub efforts are another matter entirely: YPC5 seems to somehow repel attempts at translation. The first season, which ran from February 2007 to January 2008, was finally fully translated in October 2012, and even then only as a hodgepodge of several distinct translation efforts. The second season, which ran from February 2008 to January 2009, remains unfinished as of June 2013. Fortunately there are only four episodes unsubbed thanks to the work of two separate translation groups, with one of them subbing the series backwards so that the whole series can be subbed faster. And as of December 2013... it's finally subbed fully
Franchise Killer: Believe it or not, GOGO, with it's poor ratings and merchandise sales, nearly killed the Pretty Cure franchise. Had The season following it, Fresh Pretty Cure!, failed finacially, it would of been the last series after this one because of how badly it did.
Portmanteau Series Nickname: Though it was common before, this series, particularly with its caption-less logo, made it look quite likely that both "Pretty Cure" and "Precure" are canon, both for the name of the series and for the name of the group. Later seasons of Pretty Cure actually use "Precure" in the English caption.