But I really dislike the way the most interesting Klingon woman we've ever seen is dispatched quickly and horribly off-camera, leaving the double implication that she underestimated her opponent and couldn't defend herself.
Given that we've seen women kick a** and take names on Star Trek prior to this, wouldn't it be more fair to say that we're left with the [rather logical] implication that a politician/diplomat couldn't defend herself against a trained warrior?
As for underestimating her opponent -- I think you're reading too much politics into the scene. If it was Picard getting in the face of a Klingon warrior, you'd call it a master's diplomacy -- even if he'd be killed should the opponent not react as expected. K'Ehleyr does the same, and she's an idiot.