I'm no expert! I do like her though, I think she looks like a beautiful, fun horse. She won't be a high-level horse in any English discipline simply because of her conformation but for the lower levels she certainly looks like she would be a lot of fun and could well be very successful. She could make a higher-level Western horse, but I really don't know enough about Western disciplines to comment. I think she's a lovely horse with a very QH look about her, and if she is QH, that's what you want - a horse true to the breed's type. I love them, by the way - I just have big dreams for English disciplines.
Oh, also, I have a thing for duns, so even just her colour would be enough to make her one of my fav HF horses! (I have a buckskin, very similar in colour but without any of the dun factor markings - dorsal stripe, zebra barring on the legs)
Edit; the only thing to be aware of with those straight stifles is that she MIGHT have some issues with them locking - straight stifles make horses much more prone to such problems - but as she is a mature horse, if she doesn't already have stifle lock, she probably won't develop it.