Scion was one of those games that really could have gone well but, unfortunately came at the wrong time. White Wolf's merger with CCP happened in November of 2006 and Scion Hero released April 2007. Most of Hero was finished before the merger so much of the editing and management decisions were done by White Wolf. After that CCP seemed to have no fucks to give.
A lot of the WoD books suffered but so did Scion. There was no playtesting that I knew of. I am happy that everything has started to get back on track for WW. They are now Onyx Path and have a lot more oversight on their own stuff, including public playtesting and taking advice for content from the forums. Along with all the other awesome stuff we're getting now (God Machine Chronicles, Demon the Frutang, Exalted 3e), Scion is getting a second edition.
Really, most of the problems stemmed from CCP. They only acquired WW so that they could make the MMO, which is on hold again or at least it's not been updated for over a year. CCP was highly secretive about everything when it came to the books. Most of the time there was never a release date until it was released. Along with this there was no playtesting and from what I can tell they fired all of the editors. Don't believe me? Check out the original version of Geist. There's a 50 something page thread of nothing but errata for it on the WW forum.