Alas, this series is over now. Such bittersweet feelings. A grown man isn't supposed to get this emotional over a TV series aimed at preteens. It's such a good show though, definitely another feather in the cap fer Madhouse.
I never did expect to see Souta paired up with anyone in a romantic sense of the word. While Ringo expects to have some future with him in a mothering sort of way, the only person she seemed to have a true rapport with was Hameln. His pseudo-father role complements her pseudo-mother one. Honestly, this show seems aimed at an age bracket that isn't yet too concerned with relationship issues. The near-total lack of sexuality was kind of a relief actually, it's nice to have a show where only the women have boobs. Ibara's outfit does contain a token suggestion of a bra, but she also seems like the oldest of the girls. IMHO Gretel only has sex appeal because we're so conditioned to think that way about any female wearing a maidlike outfit with lace.
Spoiler for For ep. 39 (end):
In the end Ringo sadly didn't have much role to play, did she? It seems as though Souta's awakening to his power has moved him beyond the mundane abilities of a girl like her. The final shots with Akazukin had a lot of foreshadowing. In a literal sense.
I think that the whole ending is metaphorical for not being ready for romance, in fact. That whole business about hearts needing to grow before the worlds could be together could apply just as well to him and Akazukin not being ready for adult life together. Would explain how come it's okay to leave his mom in Erde. I'm glad it's not a happy ending in that sense, it works better as a kid's show if the ending isn't about having the kids' lives being "happily ever after". It's certainly true of the real tales that this series is inspired by, the actual Grimm stuff tends to end kind of... grim. This way it gives more of a message about the limits of being a kid, as well as a future to look forward to creating.
I'm not expecting to see a sequel to this. Besides having gotten most of the mileage out of the source tales' material, what would the plot consist of? Shirayukihime beating down the witch that stole her father isn't going to take us very far. Souta could go and fully redeem Cendrillon somehow, but what then? She is so overcome with guilt and remorse that she spends the rest of her life in Erde working in a soup kitchen for the homeless? Mebbe Hansel and Gretel turn their candy house into a bakery and... hire a guy with solar hands! It's the new crossover spinoff, Otogi-Jushi Yakitakin!
I think I will go stand quietly in a corner now and bang my head into the wall.