It's bad, sure, but it could be way fucking worse and it probably will be if an unstable bitch like Meteora comes to rule.
It's not a problem of her being physically a monster, it's her being one mentally. She fucking maimed a bunch of little girls just cause and then blew up a guy cause he rejected her.
My guess is that in Divide, Star will give Meteora the kingdom and the wand, and Meteora will fuck shit up royally from there, dividing the country again after all the peace it had built up.
Then Conquer will involve Star and the rest of Mewni rising up and retaking the central kingdom, with a moment at the end where Star finally realizes she may not be perfect, but she is the best bet Mewni has at finally getting better.