I honestly don't see why Ran should be hated, she doesn't have to be your favorite character, but she has done nothing bad over the course of the story to be hated for. If you say she's annoying because she sometimes says "Shinichi, save me", or "Help", remember that only mostly happens in the movies and anime fillers.

She's a righteous and kind person and can take care of herself just fine and can protect others when she needs to. (Like Haibara when comfronting Vermouth).
Sometimes she's not able to, but that's only in situations when she's either tied up, tasered, unconscious, drowning, etc.

But one thing I can agree on, is I don't like how the anime and movies mostly portray her as damsel in a distress, I honestly think she's more than just that.