I think the reason people tend to dislike most disney female characters nowadays is because they basically all have the same personality. It's always the 'nice girl with insecurities who ends up getting everything she wants anyways'. Obviously there's nothing inherently wrong about that, but disney has been puttting out the same main character for years (literally every dcom) and I personally think it's unfair because girls are so diverse in terms of personnality!

(I also think that explains why people like the 'mean girl' so much more than the main character, because she's different and doesn't fit into what society expects a girl to be like)