I was never bothered by her crying. I actually really like how open she is, even if it makes some perceive her as clingy and annoying. I consider her to be a strong female lead because she's super honest with herself and doesn't shy away from displaying emotion. Her actions and feelings have always been justifiable to me. She's young, inexperienced, and was neglected for a long time. Her being the way she is after all she's been through makes her an awesome character to me. She doesn't let her shortcomings get in the way, she always tries to circumvent the blanks in her knowledge to get the answers she needs. I honestly don't mind having an FL that cries often, unless it's in the middle of a battlefield and they become a hindrance to others.
I think Erin is a good character. A lot of people seemed to prefer a 'badass' female which in my opinion, is not a good representation of a strong female lead. A strong character is one that has flaws, is not perfect and has strengths in different area.
Having a physically strong and smart character, who is able to overcome all challenges by herself makes the rest of the characters in the story useless. There is no point in developing such characters.
I don't see why female characters who cry are considered weak. I think she is strong willed and is someone who will do anything to protect the ones she love, even to the point of sacrificing herself.