The difference is that each of the women arrived where they should have in terms of corruption at the climax of the plot, there just hasn't really been enough plot development to match. The women have all more or less betrayed everything they once stood for and don't even realize how far they've fallen and in many ways they've cucked the women they should be nearly as badly as Rose has cucked her so called boyfriend. The problem isn't how corrupted the women are; the problem is that Leto didn't start learning anything about what the duke is actually up to until the very last minute.
Leto feels like a random villager because he's refused the call to action at basically every juncture. The duke made repeated attempts to upgrade Leto's social and professional status so he can be a useful pawn and while Leto's decisions to resist the duke's attempts to uplift him have been correct it means he's been kept as an observer instead of a participant. So when important things happen Leto isn't guarding something critical for the duke or taking part in guard activities that would give him a hint as to what is happening, he's in his apartment reading a book, or making a spiral emote as someone does something slutty in his general vicinity, or he's possibly even asleep. How corrupt the women are isn't the problem; the problem is Leto.