Hao had already died, twice, and had all the techniques that Anna had, why didn't he go and search his mom? 1k years and he didn't think about it? The whole plot could have solved itself if hao with his incredible powers decided to call his mom on his own.
And yeah, he was strong and smart and all that. Presenting it from the begining as impossible just demoralized anything that the series would throw at us. The feeling of "overcoming your obstacles through hard work!" that shonen should have was ignored.
For what? If the main characters had done anything to actualy stop Hao, or present a convincing argument that mankind didn't deserve to be extinguished, but no.
He wasn't defeated through the power of friendship, hard work or asspull, he was not defeated because Takei didn't plan on how to beat him in any way that would be satisfactory.
The anoying thing is that quickly reading flowers, takei is talented, the Zero squad story is pretty cool, and he at least is critical enough to point to the idiocy of the kamikaze pilots, his O.S. designs are still cool. Yes he has talent, and it's not a hack, but he hasn't finished a good manga.