I don't know if dmc was failing with western gamers because of it's japanese roots. There are lot of properties that do well over here even if they are from japan and anime-ish. For example Persona 4, kingdom hearts and most fighting games do well despite being anime-ish.
I do think it needed a change so I would bought some talent from marvel or dc to come work on the story as they are use to sorting out messy continuities. Or call in UDON, which is a comic book company famous for adapting the story of Street fighter and other properties into comics. They seem to know what they are doing.
I do think Vezlid was right tho in saying there are other ways to have westernized other than what they have chosen for DmC.