Turns out Octopath Traveler almost had some more detailed HD Rumble features, but the dev team decided to tone things down for the final release. In the latest issue of Nintendo Dream, Producer Tomoya Asano explains the team's original ideas for HD Rumble.
Well, it was mainly Acquire’s idea to utilize the features. When we first started development, we tried it out on all kinds of different things – we even tried it out on footsteps. For example, when walking on snow or grasslands, it would have a sort of “crunch” to it. But we realized shortly after that having the controller constantly rumble was not great in terms of playability. (Nervous laughter) HD Rumble is fascinating tech, though, so we ended up using it in places where something big happens, when characters break an enemy’s defense in battle, on status effects and the like. We realized that if we used it when the flow of battle suddenly changed, it provided the player with a more exhilarating feeling than they would normally feel.