whilst that may be true, the reason i classify dg as an upgrade to edl is because the dg aura adds the same as edl(health energy divine chaos resist) where as occult adds no auro or any form of divine damage.DG is more like an upgrade to Occult, rather than EDL. You can go straight to DG without doing the Warden armor quest line.
Dg could also be seen as on par with edl in some ways. One being for dps one being for more tank/survival or a mixture of both while keeping aura of edl.