Fairly usual in TB feet, where on a normal horse you have a good amount of heel, if you look from the side (with the foot on the ground) there is some hoof between the shoe and the coronary (sp) band towards the back of the shoe, in TBs there is very little, if you look at the foot from above (whilst holding it) the shoe is pretty much on the bulbs of heel. It is also usual with a long toe, the foot grows outwards and squashes the heels. Sorry rambling explanation, this is not ideal but if the horse has enough foot for the size of its body it can be managed and rectified, sometimes using bar shoes, or by careful, regular shoeing, keeping the toe short.
Yes, I would buy a horse with them if that were it only fault but depends what the rest of its conformation is like and what you would be using the horse for