So after the final episode of Volume 3, I was left thinking "Wow, Ruby is the Winter Maiden? Cool, albeit a little Mary-sue-ish."
But recent research has turned-up forums of people discussing this, and there seems to be an even split of people who think that what happened with Ruby when she saw Cinder kill Pyrrha actually has something to do with the weird "Silver-Eyed Warrior" story Qrow told her at the end.
Personally, I think that the silver eye story is completely unrelated, a way of helping Ruby cope without explicitly saying "You are the Winter Maiden" so she doesn't have to take it all in at once(I mean, her sister just lost her arm, and she saw two friends die right in front of her). An ulterior motive for this would also be that she wouldn't accidentally tell somebody that she was in fact, the Winter Maiden, because Ruby can be a bit naive at times.
Speaking my piece on this note I think Ruby being the winter maiden would be too easy a cop out to just have her already be the winter maiden. Now if she happens to inherit the power later on from the actual current winter maiden as a means to beat the big bad seems a bit less "deus ex machina" and would allow for her to develop her huntress skills through more experience and less plot armor kind of way.
Now onto the silver eyed warrior thing I think it alludes to something other than maidenhood as well (though this still feels like a cheap level up we haven't seen her instantly become god from just having silver eyes... yet.)