This has long irked me as well, it's amost as if after having her tell Namor she doesn't hate men, she just knows she's their equal, someone at Marvel decided "oh no, we're having none of that...". Of course prior to The Defenders I think she only had two other appearances, first in The Avengers as a disguised Enchantress, and then the Hulk issue (Samantha Parrington infused with Valkyrie's spirit by the Enchantress) where she pretty much hands ol' jade jaw his own backside, she even exhibited concussive energy blasts with her spear in that story, though one could always say she was amped by Amora's magic. So, essentially, at the time she was added to The Defenders roster, she only had a loosely defined power set which only really solidified once she became a recurring character. Unfortunately, her strength level was wiidly inconsistent, from being near ineffective to taking out over a dozen other super beings (yes, most were Z list pushovers) without breaking a sweat during a berserker rage, and subsequently over the years, most writers, and readers, tended to put more emphasis on her low showings.