Don't even get me started on that abomination. My new issue with this notion of ascension, then why is there so much discontinuity between the 3 of them? Wouldn't they have needed to reached the same level in similar fashions? Unless....only Father reached this ascended state, and Son and Daughter are off-chutes of his being.
I always thought the Daughter and the Son were children born of the Force, and the Father was only given a GREATLY prolonged life and power to keep them in balance. When he failed to do that the Servant was the one who taught Daughter and Son to work together. More over, the Servant and later Mother taught Daughter to have unlimited compassion for her brother. Which is why Daughter continually believes in the goodness of the Son.
But since Father is dying it was Anakin's destiny to become The Father because he had the power to tame both children. The Father was most definitely a mortal man, but the children are eternal to an extent, up til Daugher sacrificed herself, and Father took the Son's invincibility from him.
I also don't think the arc was fan service. It was supposed to explore the Chosen One, and actually kill Ahsoka so she could become this strange half entity, I'm curious to see Daughter's powers within Ahsoka. Either ways, that's my put on the whole Mortis Arc.