I believe breeders liked Leo Hancock Hayes because of his foundation breeding and because of the great bone he possessed, as so many lines of horses are losing or have lost, that good solid 'bone.'
However, when I was in Texas and Oklahoma recently, there were more good-boned horses than I expected there to be.
Oh, yes, Blue Valentine's picture makes him look like a real bronc. Leo Hancock Hays was not a beautiful horse, but his conformation was correct and his muscling was good. You could tell had the mark of a good sire. To me, they either have that, or they don't...and many don't...
Leo Hancock Hayes is a using horse type sire, not a halter horse type.
Guess that's what I was trying to say.