There were a BUNCH of things wrong, but in short, they remove the "Mulan feel' to the movie...
Mulan was ALREADY great at fighting but in the cartoon, she was JUST LIKE EVERY OTHER GIRL. In this movie they make her to be a character that is 'not like other girls' but that wasn't the case in the original. This is what also made the show lack character development, because the entire reason for her going to fight in the war was to protect her father, at least in the original. In the 2020 version it was mostly because it was ''all she ever dreamt of doing''
SECONDLY, where Mushu at? He literally made the show what it was. He was Mulan's companion. Not some phoenix spirit.
Overall, this movie was only action and was lacking story plot and something entertaining. I was honestly EXTREMELY disappointed. So glad I didn't go in cinema to watch this.