I love Agatha as this very wise woman with vast ancient knowledge, who regards the likes of Thor as young whippersnappers, who can be kind of creepy and scary, snarky but can be deadly serious, but with a heart of gold.
I think what adds weight to her relationship with Wanda is Agatha never having had a daughter, and the passing down of knowledge from mother to daughter, being a big deal with Witches. So for Agatha, it's a very emotional thing. Just as Strange was the person AO had been looking for, so Wanda is the one for Agatha.
I love the idea of a scene between Ancient One and Agatha Harkness, these two great teachers.