It may be attractive, but it completely undoes a major aspect of Sanjis character and that his fire comes from his passion. If you undo his emotions you’re erasing his passion and I don’t think there’d be much interest in a Sanji without his fire going against the straw hats.
As they say, passion kills.
Besides, it’s Oda so I would expect a happy ending after Luffy steps into to do his job as captain and punches the shit out of Sanji to bring him back to his senses. G5 might just be capable of that.
Curing Sanji could also be a major milestone in Chopper’s development as a doctor. Maybe this would coincide with Law reappearing and helping out. Who knows, Oda is a very good writer.
That’s also why I think he’ll pass on this storyline. He kinda already did something similar with Sanji in WCI so I don’t think he’d do it unless he had something interesting to say with it.