I've seen different opinion on that. Some wanted her dead, other thought it was fair enough.

I personally liked Freya a lot, probably one of the most complex and well written characters. So to me the punishment that she would get in the end does not really matter, as long as it was consistent with everything else.

If she was sent back to heaven, we don't know what would happen to all the high level adventurers of her Familia. So, I guess keeping her around was just to also keep them around as Orario will need them later on. It was the most logical choice.

It's not like she just got slapped & it was all over, she's still amending herself by doing community service & who know how long it could last, working for centuries or millennia is not exactly an enviable fate.

Beside in volume 8, Ares' actions were clearly said serious enough to desever to be send back but wasn't because of the negative impact it would have on the childrend living in Rakia. So not sending Freya back to heaven wasn't a bad decision, it just shows that the Gods prioritize the safety of the Lower World having still to be deal with OEBD over their own personal grudges.

I am amazed though in how the children of Loki kept their composure and emotions in how Freya treated them.

Emiya, that is known as plot convenience, both Loki and her children were so upset with Freya that they attacked Folkvangr but since Omori didn't want any of them to participate in the wargame, he magically made their anger go away.