I am fully okay with this plan. Talks are being had about this very thing. Raven would not shift into Negan for awhile, not unless she was feeling emotionally compromised or she felt that she had adopted his mannerisms so well to fool Harley completely. But trust me when I say that she will make an attempt. Raven knows complicated. She can relate all too well. There's charisma there and Negan has it in spades.