Kratos only works as an angry vengeful killer, when you try and change him to be more "human " you get shit like ascension.
Just leave the character and franchise the way it is.
Not really. There are 3 dimensions to the issue: 1. Story, 2. Execution. 3. Previous characterization. It's a hard pill to swallow to try and characterize differently a character like Kratos given the way SSM did for the first three games. Not necessarily different (as in a "new character") mind you, just adding layers and expanding. It's tricky to write a story that tries to add dimensions to Kratos that you wouldn't normally associate with him (big contrast traits) due to how light some of those traits were touched in the first 3 games. Expectations from players play a big role in how something sticks. Add to that the complexities of game development - you have to execute with gameplay, narrative, acting, animation etc etc - execution overall.
Kratos was a family man. Kratos was a loving father, and husband. Kratos was a fierce warrior that commanded his fellow soldiers with respect. Kratos was a protector of lands. Kratos was also betrayed by the Gods in a multitude of ways. Almost each betrayal (and his quest for revenge) taking up 1 game. The loss of his family drove him mad, devoid of his former self, a sociopath, a killer, a mad man. If anything, it's a mark on SSM cap when people criticize Kratos portrayal and characterization. It's like that villain you just love to hate. You hate him because he's such disgustingly evil, villainous etc... Well he has done his job well if you hate him. It's no surprise to me that after Kratos's rampage in GOW3 people are just about as done with Kratos as the story is with itself. I was too.
As you say it's rather easier to avoid the complication, the complexity of the task (making another game with him) and do another protagonist with a clean slate where they practically design from scratch and have creative freedom.
I applaud what they tried to do with Ascension - as a spin off. Worked out well for the most part.