Custom Occult Sims CAS Option...

Hey! This actually seems like a brilliant idea!
Being able to create your very own Occult Sims!
Not exactly how it will work or if it will ever work, but I can see it now!
Want a fairy, witch, werewolf, mermaid, genie, angel, demon, or even a god?! Just go right to CAO (Create An Occult) and start choosing your perks, flaws, Hidden/Second Appearance/Form, abilities, needs, and requirements. Then just give your occult a name then send them out into the world!
It would be like making your very own little Frankenstein's monster.
So kind of like Spore, but not really. Since it should be more advanced and doesn't deal with evolution.

Though again; Don't know how this can really be implemented or if it can be implemented without issues. We got to consider what makes an occult sim an occult sim and how will our player made creatures will interact with other Sims and objects. Will there be bugs, clipping issues, and/or game stopping drawbacks?
Will the abilities, perks, quirks, and disadvantages be limited? Can the game itself make it to where I truly can create an occult the exact way I've imagined/wanted my occult to be? What if I want say... A shape shifter! Can my custom occult sim have more than one hidden/alternative form? Can I make it to where he/she can mimic other Sims' appearance?

I see the potential in this idea, but it does sound a bit like a pipe dream knowing the game's and engine's limitations.
So maybe the idea isn't exactly so brilliant, but hey! You never know. Perhaps our doubts and expectations can be exceeded!