Making it two feats would make it more attractive feats to more(Mostly martial) classes as at epic levels, picking feats are really important for builds and at most, they can only have 7-9 feats to choose especially for Barbarian since pure Barbarian can only get 3 bonus feats and even with 4 class of fighter, they would get at least 5 bonus feats.
Each EDR can be readjust to 4+ DR and the second EDR can be 4+ DR or 5+ DR.