Mate, there is Imu and Loki that haven't even been fully fleshed out yet and there's also Nika. I'm not saying Sanji cannot and does not get special focus. I'm saying I don't really see the sense in Evil Sanji here with all that is going on right now nor any narrative reason for it. Why would the focus suddenly be on Evil Sanji? Moreover what is so special about Sanji becoming evil from getting Domi-Reversi-ed. In this instance it'd be no different from anyone else.
Sanji turning evil from Germa transformation makes more narrative sense than Sanji getting turned evil due to a gimmic that would apply to anyone else if Oda really wants to go the route of making Sanji lose himself.
Narrative reason for evil Sanji is that this is a reasonable reason for :
- CoC unlock (because DR is being controlled, and CoC=overcame it)
- Sanji hurting women (DR is berserk mode)
- Finished Sanji asking Zoro to disable him subplot from Wano
- Germa can turn him evil, why need Imu? This time it can be about Sora and what's special about her (which IMO is the origin of Jambe fires)
So yeah, he is different from everyone else because his character has weight and previous subplot that can be concluded.
Every other SH doesn't even have their own storyline, making them getting DR-ed feels random, sudden, & having no essence.