How would you rework it?
If the motive was to not have heph for every major god, I think artemis would make more sense than hera. The lightning storm god power is more of a Zeus 2 power than a hera power and argive patronage plays into the zeus specific unit. Hera is designed to be very zeus specific, so seeing these things on demeter is weird.
Having earthquake instead of lightning would also help against buildings more. Demeter is a tad lacking in siege (potentially by design?) so earthquake would help cover that weakness.
Also, colossus being able to eat midas gold mines was super cool and felt great to pull off (for like the one time I was able to do it in a real game). The eco focused heph also played into the eco focused demeter.
If Hera was the other choice in the first place, I’d assume the motive was to break exclusivities, like Freyr did with Hel who was exclusive to Loki before that. She doesnt really fit Freyr all that much. But eh. It’s not like Baldr would have been much better. And everyone has access to Tyr, like everyone has access to Hephaestos.
Now, I don’t think there is any motive beyond “Just do something, so it looks like we’re trying to fix the DLC”
I originally didn’t want Hephaestus since all the other Greek major gods had him as an option. However having played with him using Demeter I changed my mind. I enjoyed having the plenty vault and a strong myth unit that also works with King Midas. I think that is a cool interaction and it’s a shame you can’t use it anymore. For argive patronage I would personally like it reworked to provide the free unique fortress unit for each major god. I’m not a fan of Demeter getting Zeus’s exclusive unit.