Ziz doesn't actually have perfect precog. Her precog is very, very good, but even without the holes it's still not perfect.
Anyway, you can have perfect precog as well as let free will exist. All you need is for using precognition to "choose" which future you'll end up in. Anyone who would go to a different future would get the precog for that one, instead. (If you don't follow it, though, who knows)
What about PtV- It never has a problem modeling humans, or even entities before Eden put some restrictions on it.
Also, given that it is said that there are a limited number of universes in the Worm-verse, and presumably no new ones. how can pre-cog be choosing which future occurs without taking away free will (and thus forcing it's our future) itself?
Out right raping Vicky. This is the point where Amy goes from an ambiguous person to a bad person. Vicky isn't "better off" being raped by Amy. For one we have no reason in canon to think her and Dean have anything but a positive relationship. But Amy is no better than Heartbreaker here. She is forcing Vicky against her will to be her love slave. This is rape. That can't be argued. And at no point can I accept rape as some net good for people.
First off we don't know that they will be having sex so it
could be just sexual abuse or whatever the closest equivalent would be, also even if they did have sex, it would be rape legally only in-so-far-as Victoria is under the influence of mind alteration, but that would mean that Amy would be raped as well because of Victoria's aura, and given that these changes are mostly permeant, it seems that even sexual abuse is not descriptive of this event. Please stop using the word rape without
knowing that it is rape.- but that isn't very important. Love Slave is also an exaggeration.
As for the rest... I mean, I guess? But you have to see, our brains are constantly changed by things outside of our control, so how is Amy changing a brain any different? And if you believe that her changing of Victoria's brain is actually replacing/killing Victoria, then how would you be the same you from 2 days ago (at least in the worm-verse), your brain is distinctly different, after all.
You can't take away free-will if it doesn't exist.
EDIT: wow, a lot happened while I was writing the post, maybe I forgot to refresh the page.
EDIT2:added some stuff to the 'It's not rape' part.