I liked Road Warrior, but you cannot really compare it to this new Mad Max. Road Warrior was a continuation of the original Mad Max, so the character had already been developed, so that allows for some leeway there. Plus, let's be honest, it's road race/war scenes beat the crap out of this new Mad Max's ones, it's villain was far superior. It was just better in every way. Okay, I guess you can compare it to the new Mad Max. 
Exactly what character development do you need? Max is an achetype. It's instantly there.. not developed. Like Clint in Spaghetti Westerns. Or Charles Bronson. The man with no name.
Again, it was setting itself up to be compared to the original Mad Max because, you know, it calls itself Mad Max. GIven that, its lack of character development compared to the original was glaring.