Physically he looks more like an Irish warmblood than a 'modern' Thoroughbred. Today's racers have the "greyhound" build which does allow for a greater stride and speed but tends to sacrifice general bulk and bone density.
Look at those hindquarters! Beautiful!
Breeding is such a mixed blessing. I have a little Morgan - Morgans actually are indistinguishable from Welsh cobs, genetically speaking, but trace their lineage back to Justin Morgan's horse - and my little guy, barely over pony size, was the original Morgan size. They are now breeding them to be enormous, usually crossing them with warmbloods, stretching them out for dressage purposes because of their intelligence and stride. Still, it always makes me uneasy when I meet a Morgan who is nearly 17 hands!