I think 343i really went into the whole Spartan-IV thing without thinking too much about it. Prior to Halo 4, Spartan-IVs were seen in the works of fan fiction and idle speculation. I mean naturally they make sense, normal, everyday people finally given the armor and enhancements of Spartans. We started with adults in the ORION Project, which ended in limited success, to kids who had a higher chance of succeeding and then through years of research we were finally able to bring back the Spartans to their roots. However, they just happened. Both the S-IIs and S-IIIs got books and other forms of media dedicated to their origins, the S-Is are more behind-the-scenes sadly, but the S-IVs were introduced in a ViDoc about the multiplayer and just show up in the Campaign with Chief not so much as giving a damn as opposed to someone like Kurt-051 in Ghost of Onyx being awed by the prospect of thousands of new Spartans. Halo: Initiation looks like it will expand on their origins and such, but shouldn't have that been before the game came out so we could've gotten a better chance to know these Spartans? It is the same problem the Ur-Didact had in Halo 4, all the good stuff that makes him an amazing character and terrifying villain was left in Halo: Silentium, released 5 MONTHS after Halo 4 came out.