Pacts will only be made with exclusives / muses that would make sense. Most often being either characters that are chaotic, or destructive. Or ones that are trying so hard to redeem themselves and step away from that path.
The set time thing has been removed. She can be with a host as long as she, or her host would like- but the side effects of a prolonged pact are still present. Effects include: changes in mannerisms, accent, ideals, interests, and even appearance in super extreme cases.
These effects are most often permanent.
It’s rare that she will actually kill her host, no matter how much she seems to hate them. Sharing a body with someone can lead to some serious attachment issues.
There can be no secrets between her and her host.
Creating the pact is still painful, but ending a pact is not. If a pact has been active for a long time, both her and her host essentially become depressed / angry about it ending. She always recovers from this fairly quickly– but how quick her host recovers, depends on who it is.
The only things she cannot make a pact with, are Celestials, and Yordles. Technically she could make them with residents of the Void- but likely wont.
Edit: Hosts can see her Eldritch nature much easier than most anyone can. Be it through thoughts and dreams, or physically.