People are very bad at explaining what they like about things, because usually they like things in contrast to things they don’t like. And people who do identify what they like positively often just get told that their input isn’t welcome, either.
The problem isn’t whether someone is focusing on negative aspects of what you’re playing or the positive aspects of what they are, it’s that discussions about minority systems are often just puked up onto people who weren’t asking. The conversation is often:
“Hey, how can I do [thing] in [game I’m playing]?”
“[Game you’re playing] sucks at [thing]/isn’t designed for [thing]. You should play [something else].”
“But I like [game I’m playing], and don’t want to convert to a whole new system.”
This means not only is the asker’s question being totally ignored, but they’re being hit with – sometimes even bombarded by – value judgements they weren’t interested in.
Try explaining things to her in more intuitive terms. She gets to do more damage when her opponent has significant trouble defending themselves. That happens when they have to split their attention across a wide distance (flanked), when they’re on the ground (prone), when they can’t see where they’re being attacked from (hidden), or when you fake them out (feint).
Old hats tend to boil away the actual roleplay from combat, but the rules usually directly support a roleplay-based view of battle. Presenting the game this way had my then-9-year-old picking the game up really quickly.