Who says she can't do both?
My boy is super slow and laid back, but manages to excel in both the hunters and the jumpers. When we get more training in him he'll hopefully by doing the A/O hunters, 1.10 m jumpers, and 3'3" equitation by the summer.
And blush, I don't know if I agree with you. The best hunters I've seen are slow and laid back with a big, powerful stride to get down the lines. The horse I was talking about before has the ideal stride for the 3'6" hunters, despite him being slow and 15.2 1/2 hh. We have to collect him so much for anything smaller. My TB is also a hunter who is 15.3, but has a stride on the smaller side, fortunately he's spirited enough to make the stride, but, while it's nice, he doesn't have the same effortless look that the first gelding has.