Personally I would want to see the dangers of corruption, during the game we see multiple characters that are falling to their corruption or that are at risk of being attacked but nothing happens no matter how much time passes, even more it would be nice that territories had a "corrupted stat" that showed how dangerous it is becoming, just to give a few of the situations I mean:
In general, I'd also love for Corruption to eventually become both a more significant threat requiring a more proactive approach from the Champ AND a more developed source of extreme sexual content. Even knowing that is is a ton of extra work for the writers involved, I still think that the result will be worth it. However for reasons listed below I think any such development should take place in mid-to-late game:
Time gating is most likely out of the question from the get-go, since the devs expressed their desire to leave the day counter entirely decoupled from all the plot progression. Which leaves us with either event specific triggers for the corruption progression of each individual character and zone, or ones based entirely on progressing between the Acts.
Out of the three Acts planned, Act 1 is so open and freeform that implementing such a mechanic can really screw over any new players that don't follow wiki or guides. At the same time, the main quest points the player directly towards two major sources of corruption in the early game (Alraune and Winter City); dealing with one more (Centaur Village) is mandatory before the player can reach Khor'Minos and Act 2 proper without attacking minotaur guards and potentially turning a lot of their city hostile. All that doesn't leave much corruption to propagate and take over characters and zones without the player nurturing it and facilitating its spread.
In contrast, I imagine that by the end of Act 2 Kas's plans will kick into high gear and her invasion will finally come in full force. Changing zones and any characters left roaming them unprotected to reflect this shift is a tried and true trope for both western and Japanese RPGs.
Another thing that can limit the implementation of passive corruption is the fact that from the pure game feel perspective, a more hands-on approach is preferable nine times out of ten. Because when you just didn't get to meet the character enough times or do enough in a particular zone and then you return to find it corrupted - it feels like a frustrating failure. But if you have had a hand in the transformation or explicitely chose to leave a certain place or peoples to their fate, the resulting changes are satisfying fruits of your labor or just desserts you served to some assholes.
I think the later scenes should reveal that she is totally Baba Yaga. Saggy tits, gnarled teeth, crooked claw-like fingernails, and wiry, gray pubes and all.And then she steals one of your babies... or has one of your babies.
Okay... maybe that should be set aside for a dream scene.
So something like this:
Though personally I'd prefer a less common and more cultured beefy route:
