Argh, I typed a reply and then lost my internet connection and it deleted everything :/
In my opinion, if the horse has muscle wastage and wears unevenly on one of his hooves, I would be concerned that there is an underlying issue/injury that you have not been made aware of, or else it could develope into one later.
Also, the fact that they were a tad sly about the loading issue would send a huge red flag up for me as to what else they are not being entirely honest about.
Saying all of that, if you like the horse, by all means best of luck. We all know half the battle on finding a horse is having that "click" with one in particular :)
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.