Fear of bodily harm just is not an acceptable standard for self defense. The standard should be an actual legitimate threat to your life. I wouldn't be able to morally vote not guilty here, despite the letter of the law.
If by legitimate, you mean reasonable, then I don't think you're too far off the current standard, minus the serious bodily harm stuff. And if youre ever in this situation, I think you'd be glad the jury (hopefully) isn't debating "well maybe he would have gotten beat up pretty bad, but was he really reasonable to think he might die?" No, you'll hope like hell the jury isn't second guessing your decision making while your head is being banged into a concrete sidewalk.
The standard isn't the "problem" here. The problem is that there's almost no evidence of how the fight started, only a little more evidence of how the fight went down, and that evidence tends to support GZ's side of the story, which is inconvenient for those who want him to be guilty.
