The concept of the Changing God was not the problem. In fact, it is quite unique and fascinating, much like Pillars of Eternity's concept of souls. The main narrative, however, was mediocre, and its emotional core a wispy shadow of Planescape: Torment's. The story lacks pathos - the Changing God, whether he is actually the player, as heavily implied, or an external entity who simply happened to occupy the player's body, has no discernibly sympathetic aspect. He is portrayed as arrogant and indifferent, whose sole redeeming quality is an external event involving the age old cliche of having lost his daughter & wanting to revive her. Maybe McComb is referring to being a parent when he says he's now much older and cares about different questions, but the fact remains that we've seen this variation of a motivation a hundred times and TTON brings nothing new to the dynamic. Not to mention, there is minimal development for the Changing God's daughter and her relationship with her father, so the entire motivation is abstract, more so because the Changing God is portrayed as a pathetic parent figure throughout the game, which I guess is supposed to be ironic, but in actuality makes no sense.
I don't know about the rest of the game, but the narrative could've been much better, had Miika simply been thrown out, and the emotional focus transferred to the relationships between the Changing God and his cast off children. There was the seed for a compelling story, there, around the responsibility of a creator who never intended to be a parent, and the conflict between those who blamed him for their problems & those who still loved him as their father. As much as there was a poignant moment in the game, it was the relationship between the Changing God and the First - of how he initially gave her gifts & treated her like a daughter, but ultimately abandoned her to the Sorrow, leading to her age long hatred, as well as the different reactions of the cast offs to the Changing God in the sanctuary. But in the end, these were side shows in a game that spent more time being weird than developing its emotional core, and so at the end of the story, we cared neither for the Changing God, nor his motivation, nor our own relationship to that motivation.