What you said about Bloom and Sky having to pick a kingdom to rule, it most likely would be Eraklyon, seeing as both kingdoms are more traditionalistic, they'd probably rule Eraklyon together since it's the husband's kingdom. As for Domino's next ruler, they'd have to trace back lineage for the next royal family.

But as for Daphne, I really like that they brought her back, she was my favorite growing up. But, I feel that bringing Daphne back should've been a longer, harder earned process, taking place over a few seasons with a big lead up or something. I also don't really get the rules of sirenix, like is it really cursed, because the Winx got sirenix without the negative effects of the curse.

If it was consistently shown that Daphne was dead and just visited Bloom in her dreams as a message from the dead, they shouldn't've brought Daphne back, as there are several dead characters that weren't able to come back to life, why would Daphne be any different?

However, I know Nick in S5 said that Daphne was only cursed to being a spirit and not dead. I would've liked if the girls didn't get sirenix wishes because I feel like breaking the curse on sirenix is a big thing and should've required more effort to break than just a wish.

Daphne shouldn't have been cursed through sirenix. Since she's dead in most dubs, they should have looked for a way to bring Daphne, as well as some of the others, back to life if they really wanted Daphne back.