Yeah, Dany might be a better person overall than Cersi, but she's a far far more dangerous tyrant. I think Cersi for the most part would leave everyone alone outside of KL (since she doesn't have the resources to really do much more than defend KL anyways). She can maybe retake the Iron Islands but that's probably it. They don't like Cersi, but they don't necessarily fear her either.
They fear Dany, and they now have every right to. She has the will and the ability to take Westeros by force and kill anyone who stands against her. It's a notch below the NK but several notches above Cersi, who is more bark than bite at this point. It's why Dany one way or the other needs to be stopped. Leaving Cersi on the throne is almost a more hopeful ending for Westeros than Dany at this point.