Greta will have to move to the right to fit in, especially since Fox's viewers will demand it. Greta will bring viewers from CNN, since, as I understand it, she has a pretty loyal following. Her followers will move to the right along with her.
What will CNN do to fill the time slot? If they fill it with someone who they think is conservative, then the "liberal" viewers will be turned off. If they fill it with a liberal, then it's business as usual, which is a continual slide in ratings. If nothing else, Fox has taken another swing at CNN's base.
I find this FOX vs. CNN thing to be a lot of fun to watch. FOX didn't wake up one morning and decide to hire Greta over a cup of coffee. Every move they make is carefully planned, and all consequences are evaluated. Let's wait until the plan in fully implemented before deciding it was a bad move.
Especially since the "talent" isn't going over to NBC/ABC/CBS.
However, I liked the niche that Fox carved out for themselves. I was more dismayed by the hiring of Bill Richardson as a commentator than anything else. That man has no credibility in my book, and what you need in TV news more than anything else (IMHO) is credibility.
-PJ