I don't really (honestly) understand this critique.
What's wrong in being honest?
Goro works are clearly inferior to his father's works on many levels.
He's no amateur, that's for sure, but he's no master either.
Among the best Japanese animation artists, he's probably average.
He's no Takahata, Oshii, Otomo, Anno, Watanabe, Hosoda by a long shot.
Hayao worst rated works on Rotten Tomatoes are "The cat returns" and "The wind rises" and I completely agree on that, with a rating of 88%.
Goro worst is "Earwig and the Witch" that I have not watched with a 28%, "Tales From Earthsea" that I've seen and did not like much with 38% and the best is "From Up on Poppy Hill" with 87%, which was good, but not "Spirited Away", "Princess Mononoke" or "Nausicaä of the Valley of the Wind" good.
And Nausicaa itself is not as good as a movie as the manga, that is an order of magnitude better!
Have you ever read or heard about the 3 Wolfgang Amadeus Mozart children that survived?
No?
You are not the only one.