From what we can tell the All-Seeress really WASN'T quite a person, but rather more of an prayer granting machine or animal when we took them in. They didn't have a gender or image at the time, they didn't have a name, just a title and thus the resultant god had very little personality(especially when their most devoted worshippers fought to the death when they didn't need to, removing what was left).... BREAKING NEWS, BELIEF IN ALL GODDESSES AND OTHER DEITIES HAS NOW BEEN BANNED EVERYWHERE!
Why does being a collection of thoughts and stories given form preclude you from personhood?
Humans, after all, aren't more than a highly organised collection of proteins and strategically arranged chemical imbalances.
Wyrn's project then, is to remap how she is perceived. First, becoming one of Arthyn's daughters, gaining an appearance, and a gender. Then slowly shifting the stories such that she was perceived as a taciturn, but wise deity, and then building the little quirks and interpersonal interaction which makes her a person.
After all, Wyrn's whole Thing was Personing previously not-Peoples