It's been awhile since I played the gow trilogy, but didn't Kratos go back in time to where he was killed by Zeus? Wouldn't it have made more sense if he went back in time to stop Ares before he made the vow to serve him and end up slaughtering his family? I just think that would've been a better story. But it's been awhile since I played them.and I don't remember exactly what the plot was with the sisters of fate and how he went back in time.
Time travel stories are always full of holes. Like if he went back to stop Zeus from killing him, Zeus not killing him would have meant he never would have met Gaia and never would have been sent to the Sisters of Fate to come back and stop Zeus from killing him.
If you start to analyse any time travel story it falls apart, just take it for what it is.