I do see some issue with her hinds, but agree that 'too short' is not necessarily(don't think you can say for sure from this one pic) one of them. And also agree that short(assuming not too short) is a nice change from the too long norm.
The horse you pictured to me is going through some remodeling of her back hooves ...
Now rehabbed to a riding horse,
I presume you mean they will
'remodel' if she is 'rehabbed' & cared for differently. I agree that if this youngster were 'rehabbed' - gotten out of shoes, trimmed well, on a healthy diet(as opposed to the 'high octane fuel' she's been on), etc, she will have a very good chance to grow healthy, strong feet, especially since they're in that(pretty reasonable, considering) shape after racing.
Always running one direction for workouts or races, having feet actually trimmed at 4 week intervals but often shod in-between those times...having your hooves put to a desired angle to better break-over and hit the ground at a dead run does cause lasting effects on some horses...
A question, about what you said above Karen - I'm familiar with racehorses over here, but is it common over there for them to be trimmed & shod that frequently? And done so with correct 'breakover'? I wish that were the case here - well, the trimmed 4-weekly & with good angles & breakover anyway. I don't believe shoeing that frequently(why is that done 2 weekly??) would be helpful.
Oh & yes, body issues from running in one direction, babies made to do so much at a 'dead run' as you put it(not to mention most standing around in stables/pens for the rest of their life), I'd actually say go so far as to say it has lasting effects on ALL horses. But a 3yo at least, hasn't raced all that much & is still far from mature, so, with good bodywork & care now, some of those issues at least might be 'undone' and 'corrected'.
OP I too don't like the look of her hind end - tho it might
be that her 'straight' legs are a reflection of the pelvis angle & one thing that may
be 'rehabable' with a good chiropractic vet or such.