Upon viewing the photo on my computer I do agree with you Bubba. Was on my phone so couldn't really see much, but that's what stood out to me. I do agree with the person who said they thought he was shoulder heavy, he does look to be built downhill - and no, wither height is NOT how you judge whether a horse is level or not. I'm looking at back shape and the way his whole body feels (to me) like it's going forward and down.
With pasterns like those, and a downhill build, I would still keep looking. Long pasterns are, as Bubba said, an inherent weakness in the leg, and you wouldn't want to do any high-level jumping with this horse. I don't feel that he would be capable of it anyway with the way he is built.