I can't quibble with too many of his complaints. I loved the game, and actually liked the ending as it brought Kratos full circle. As for killing the other Gods, Kratos himself says in the beginning he's bringing the destruction of Olympus. It's the Age of Twilight, after all. While not explicitly stated, it's become more than personal for Kratos, it's about ending the Greek God system. Kratos isn't in a righteous funk here; he's a part of the problem, and he admits it. "By the end, Pandora, you will not be thanking me."
I thought the game far more than a rehash. The things that didn't need to change stayed largely the same, but this game had far more style in its execution. I found the combat more responsive than in GOW2, but I agree with the weapons finding. You get the Nemesis Whip far to late in the game to want to try to use it, and the Hermes boots seem almost a throwaway (particularly for platforming.)