I agree with you that upright hitters should be better able to hit the rise or a high pitch better than hitters with more hinge. But an upright stance should make it harder to get down to a drop or a ball low in the zone. I am surprised that standing more upright when expecting a riseball isn't discussed as a strategy. In MLB the hitters guess a lot, I don't know about D1 softball. A lot of this kind of analysis is really very subjective because there are no stats about it.