The announcement of a second Leap Motion controller surprised me. My rough estimate is that I used the first version in more than fifty projects. Seeing a new version immediately brought that interest back.
Ultraleap's announcement describes a smaller device with updated cameras and a wider field of view. Those changes are interesting, but the reason I care about hand tracking remains simple: the person already has the input device, and it can move in the same space as the thing being controlled.
That apparent simplicity creates demanding design questions. A mouse has an obvious resting state on a desk. Hands are constantly doing things. They point, adjust clothing, touch the face and move while somebody talks. An interface must decide which movements are intended as commands.
I prefer a small gesture vocabulary with visible consequences. A selection should look selected. A grabbed object should clearly belong to the hand until it is released. The user should not have to guess whether the system is waiting for a gesture, tracking it, or ignoring it.
The space around the interaction matters too. Tracking has a usable region. If an object can be moved beyond it, the system needs a coherent way to end or recover the action. Otherwise a natural movement can leave the object stuck in an unexpected state.
There is also the question of effort. Holding a hand in the air is a physical action with a duration. A playful short interaction and a tool used for an hour should not demand the same posture. Good tracking can make a poor interaction more accurately exhausting.
The new hardware makes me curious about revisiting these choices with a better sensing volume and a fresh set of constraints. I would start with one clear action, then examine the moments before and after it: entering the tracked area, preparing to act, releasing and returning to rest.
Those transitions are where the interface teaches the person how to use it. The attraction of Leap Motion has always been the closeness between movement and response. The design still has to make that relationship readable, comfortable and worth repeating.