Other than the Slave Food thing, what I'd like to see with the 'banned content' side of the modded version is a more variable slave age system (unrelated to 'ideal slave age' for Beauty score purposes). Currently it's just simply 'lowest age slaves will appear' and when set, the 'molestation below age x' policy will match this setting, but what it should be instead is 'legal (sex) age'.
Using 'safe' ages as an example, if I had the setting for 'lowest age slaves will appear' at '18 years old', most slaves will appear at 18 years and older. However, you can't set the 'legal (sex) age' to be say 21, that is to say that in your Arcology, slaves (and maybe citizens) aren't legally allowed to have sex until 21. The in-game consequences for this would be that those slaves under 21 would be barred from working in the Brothel/Club/Master Suite by automatic assignment ('choose their own assignment'), though you can still assign them to those places anyway at a reputation cost (and rumour if Master Suite).
My thinking of it is more in the line of 'while underaged, they work in the Servant Quarters / Farm' with your 'adult' slaves doing the actual 'slave work'. Maybe this can give rise to a 'Black Market Brothel' as well for the Manufacturing Sector (since most Arcologies only have few Shop Sectors) where you could send underaged slaves to do prostitution for increased income, at the cost of crime per slave as you're pretty much promoting illegal prostitution. The main idea though is that with the Incubator/Nursery, one could have them be released from those Facilities below the 'legal age' (e.g. 18 in my 'safe' example), but not expect them to go straight into whoring and stuff in a kind of 'have them get used to how things are done'. Perhaps it could even be tied in with a Slave Birthday event where upon reaching 'legal age', you can choose to break them in as a 'birthday present' - I'm pretty sure an event like this already happens but for any Slave Birthday if they're still virgin I think, and the Whore/Public Servant 'milestone' event.
But beyond this I suppose FC would require more non-sexual Facilities for this to work properly as there isn't really anywhere else for underaged slaves with this idea to work at right now in big numbers. Maybe if there's another level or two to Classrooms ('Slave College') that you can send your slaves to in order to improve their Intelligence further but takes time? This would also benefit normal slaves as currently the Intelligence drink only raises Intelligence so much and even doing a body transfer doesn't improve their Intelligence (since it seems to be tied to the Slave themselves), so it feels like the only stat that can't be improved if they're too dumb to begin with.