I think if he had a decent jump for lower level eventing then I would look into what advantages and disadvantages his shoulder angle can give you. And if those long pasterns can stand the test of time and wear and tear of repetitive jumping. There's probably a few more things but I'm a barrel racer not a jumper
. Some weight and muscle would make him look like a totally different horse. When I buy a horse athlete I look at their pasterns, the power their hind quarters can offer me, the angle of the shoulder, legs, and of course their mind. Good luck in your eventer search I'm barrel horse shopping right now myself it takes awhile to find the right one.