http://www.techradar.com/news/god-of-war-release-date-news-and-rumors

Updated: In a recent interview God of War's director, Cory Barlog, offered some more details on the game's new upgrade system. 

The system has essentially been overhauled as the team aimed to "leave behind" the classic system and "contextualize” it in order to make something that's a little more fun.