GEDC originated as an outgrowth of the GEDCOM 6.0 Beta spec from the Church of Jesus Christ of Latter Day Saints. It still bears a superficial resemblance to its predecessor, but many minor changes have been made as well as several major ones.
Especially, GEDC has followed the lead of Gentech's Genealogical Data Model (GDM) and broken away from the mindset implicit in GEDCOM: that genealogical data is entirely consistent and correct. Of course it is not. GEDC makes allowance for conflicting data. It places an emphasis on complete documentation of the sources and the steps in reasoning that led the genealogist to the conclusions that he has drawn.