I can see what you mean about her being post legged. She definitely has a very upright hind leg. She has very little muscleing along her back or abdomin or gaskin or gluteal (top of rump). Her hip and sacro lumbar joint are not in a line with each other and there is a distinct bump where the Sacrolumbar (or is that LUmbosacral?) joint is. YOu can see it a few inches Behind the points of her hips. The close the two line up the better, and the way there is a minor "ski slope" going forward from that sacro joint point (toward the very flat back) means that the sacrum may be rotated a bit forward . This may be a conformational fault or it may be that her pelvis is out of alignment. Either way, it makes it hard for her to step under herself because she cannot tuck her pelvis under her (imagine the way the horse humps their back when the poo).
She has very liittle muscling along her loin and abdomin and these muscles ate the ones that the horse uses to tuck that pelvis, (same as we use our core abs to tuck our pelvis under and stand more engaged).
If things are really bad, she may need a look/see by a chiro. When you get home from Korea, you will have a job to do getting her in shape. You will be her personal trainer getting her to whip those abs in shape.
(ps I have more new drawings on my thread and more to come soon)