Yes, I think that it needs to be taken into consideration, but remember HEIGHT in itself does not determine whether a horse and rider will suit one another. A well built QH will be a much better partner for a 'stocky' built 200lb gal or guy, than a stringy tall TB, even if that QH is only 14hh. QH were bred to handle remuda work, and a decently bred one will have the bone, conformation, muscle, and stamina for the heavier work load, including a heavy ranch rider...most cowpoke ain't string beans...they need muscle you know!
I think there is more to fitting a horse and rider than just 'size' alone, because some riders buy a big horse, just because they think bigger is better, when in reality, they may not have the experience it takes to handle that larger horse. And then there's those who hang onto a smaller horse, because they like it too much, even though it may not be suitable for them size wise anymore.
It's one of those things about horse ownership that comes down to responsibility and learning what's acceptable and what's not; I don't think it's acceptable to have someone who is 200lbs on a 650lb horse; yet I've seen it done. The horse might even be close to 15hh...but as I said before, height isn't the factor here, it's weight, bone, and muscle that should be the determining factors in 'rider suitability'. But a horse who is 1000lbs, regardless of his height, would have no problems, imo carrying that same rider.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."