If thats your take away you've clearly never played the games and only read reviews about them second or third hand. No one is saying the og trilogy was bad, but according to Jaffe they were writing epics... Which frankly is a far cry from the truth and they only got better as he had less and less involvement to GoW3 being cslled the best of the trilogy, ironically the game he's not involved in making.

that most real, non childish adults don’t care for?

You are simply making things up. The reboot sold incredibly well, about 5 times more than the originals in fact, and received universal acclaim. People have grown up with the character and were happy to see that evolution. The original creator and you have become out of touch with the reality of this franchise.

Your expectation for things to never evolve and grow says more about you than you seem to want to face. But the same as you think that there are plenty of games that fill the void of deep narrative action games, I can say there are plenty of basic hack and slash games to go around, just go enjoy another one.

Not every game needs to have a background story or even a story at all!

The original GoW games had a lot of story. They didn't add more story to the new games, just better story.