She's a sexy wrenchwench, but that's not her defining quality. She's not written that way for the male gaze, she just happens to be a brilliant engineer. She's a heroine from the same mold as Princess Leia or Wonder Woman, meaning her character can't be defined by the men who surround her (hence why this page is a perfect example).
She used to be a wilting wallflower ( contrast this page with: http://www.girlgeniusonline.com/comic.php?date=20031107 ), but in the past few months she's had warrior training from her Amazonian best friend AND been put through absolute hell, so sitting down and shutting up like a good girl really isn't an option for her anymore.
So she's just now coming into her own. If you want a quick grasp of what the full realized Agatha is like, I highly recommend the radio plays linked somewhere on the official site. Hilarious stuff. :)