IIRC, Native Dancer is not the only stallion to have passed on his delicate legs to his progeny. I think Bold Ruler was up there too. Horses who have had a bunch of breakdowns in their racing careers, all too often, are retired to stud and used to breed. IMO, this is risky, but then again, I am not a horse owner.
I think thoroughbreds are beautiful, but even if someone gave me an off-the-track retired thoroughbred for free, I'd be very cautious about the deal.
I'm no expert on horses... however, *if* I had the money to have any horse I wanted, I'd probably et one of the so-called "European warmblood" horses, or maybe a Friesian, as they seem to have better, stronger bones in their legs (among other reasons). They're big and strong enough to carry a big person, and they seem more durable to me than thoroughbreds.
I just bought an Arabian. I’m 160#, and my wife is 125...we don’t need a big horse. Leg strength has more to do with proportions than size - thoroughbreds are big horses with thin legs. Good for speed, but blinding speed isn’t all.