It looks as if she is shod and trimmed for the track which completely throws off the angles of the legs. Most race horses are trimmed with very little heel, a lot of toe and often times their outer walls are longer than the inside walls. I think her back legs look a bit straight, but considering she has zero heels back there, this will change once you find a farrier who can work on the balance of her feet. Proper shoeing will also change the angle of her pasterns. I think her pasterns might look long because she doesn't have any heel. I would be more concerned to see if she has any ankle rounding, racing bracelets, set splints close to the joints, etc. She is a bit long in the cannon bone, but that shouldn't really be too much of an issue is you are keeping her as an all around pleasure horse.
Also, she has a typical tucked up racehorse body and her body shape will definitely change once she's not exercising at the track everyday. My horse had the same hoof issues I just explained but he also looked like this the day I picked him up from the track (doing 2mile gallops every day while at the track, I REALLY liked the looks of him):
He was a little over the knee when I got him (just like his sire). But his bloodlines were awesome and had EVENTER written all over them (sired by Dynaformer out of an "Shopper" family mare). With the help of my amazing farrier, he stands so balanced and has incredible movement.
With proper shoeing, preventative maintenance on her joints, and taking it slow I think you can have a very nice mare. Just keep in mind that a lot of times horses coming down off the track will experience soreness issues since their bodies are used to certain exercise on certain kinds of footing. Good luck with her, she's awfully cute.