I'm not too sure. I think I don't favor her for purely aesthetic reasons. Breaking her down, there isn't anything majorly wrong with her conformationally or otherwise. I guess it's just a brain tick that makes her strike me wrong.
Ask her owners anything and everything. Make sure to get a complete history. Know who owned and trained her, and her experiences with each of her owners. Know her medical history; ask for everything: bouts of colic, hoof problems (laminitis, corrective shoeing) ,leg problems (bowed tendons and such)... Anything.
Also, regarding special cues: people train their gaited horses in different ways. Some work almost exclusively off of seat with little leg; lean back and they speed up. My SSH is trained to take cues like a "normal horse". I lean back, she slows down; I click to gait (out of habit, I also say, "trot") and kiss to canter. Since the system isn't very standardized, it may take you a while to learn to push all the right buttons.
I understand wanting to keep the baby. I'd love to raise my own foal one day!