One thing I see is this horse is over conditioned. That is a nice way of saying too FAT. She is not a bad horse. Light boned and a bit sickle hocked and her feet are a bit small. She has a decent shoulder and a decent neck set.
I think she might lose 100 pounds and be better off. Keeping her lighter on those growing bones is a good idea too. She will NEVER get more bone. It is what it is and what she was born with.