It may seem like she always cries and experience accidents but she has always been honest and true to her feelings of love towards Rowan. I never saw her as a weak and irritating female lead. Sometimes FL doesn't need to be physically strong or too wise. Some strong points of a female lead is having a firm conviction to love that person even if she dies- and she did.
I think she's progressing. she has powers remember? she healed rowan. she also can change people(?) basically magic.
but I do get where you're coming from.. its the cliche damsel in distress kinda situation right? and the crying xD.. I was thinking.. what if rowan insist her to take sword class lessons? that'll be sweet and supportive, and Erin would become much more powerful!
Can erin like...actually do something other than always making rowan save her? Smh.