But it's true.
Marshall was a part of the GSOT. He was one of many weapons.
ED was THE weapon. Hence, the feature back designation.
The only two feature backs in the NFL now are AP and Lynch. Even McCoy and Murray were parts of offensive systems that had viable alternatives.
I dunno if Gurley will be a feature back (I hope not because I prefer a well rounded O), but I think he could be one. He has that level of skill and talent.
I would never say Faulk couldn't be a feature back (he was in Indy), but as a Ram and HoFer, he was Mr All Around Back, not Mr Feature Back.