Pretty much what the others have said. I do think however that Minfilia is permanently changed. Even though Hydaelyn isn't forced to use her as much as a crutch, I get the feeling the connection is permanent. That's why she sends Minfilia. Minfilia can act as a conduit to allow Hydaelyn to take action since she doesn't seem to be able to act independently. Even on the Source she aids the WoL through the Blessing of Light which in turn is enabled by the WoL's ownership of the Crystals of Light.