What do you want them to do about it? Air American Dad after American Idol? It already gets a pretty great lead-in with Family Guy. It's not Fox's fault the show sucks.
I don't like Roberta's new voice (it sounds too whiny and generic). It's like when Lacey Chebert (who also can have an overtly childish/girly sounding voice) voiced Meg on Family Guy before Mila Kunis. Nia Long brought much more "attitude" to the role than Reagan Gomez.
QTF. The instant I heard her new voice I thought this was the exact opposite of what was done on Family Guy. I wonder what happened with Nia Long, whether it be creative differences or contract dispute...