1. My footage is less stable. Bear in mind we both shoot the same GH4, without IS. Yet almost 80% I say mine was shaky. I considered my buoyancy control is ok, but not in the current filled water of Komodo.
2. We shoot WA most of the time, and Nu's clip can get up close and personal with the object. I used hook most of the time but I observed that Nu were free and somehow can manage the current to his advantage. Case in point was where we shooting Manta at Karang Makasar (Manta on the Moon), the current were about 3-4 knots, while I was fighting with one hand on the hook and the other on the camera Nu was free roaming and get close and personal with the Manta. My footage was just side view of the manta swimming in the current
Stability takes time to develop. Let me compare it to a racing car driver. Most people, with a bit of guidance, can get a car around an empty race track. Why can racing drivers do it multiple times faster alongside other fast-moving cars. After years of practice and experience, the race car driver's perception of the world expands to include the car. Yes, his brain builds a map of the outer edges of the car as if it was an extension of his own body - just like his fingers but further away. He can't "think" or "calculate" his way through a narrow gap at 300kmh, his brain just "feels" that the car will clear the gap. After shooting video for long enough, the camera becomes an extension of the body. Your hands, wrists and arms "mentally fuse" with the camera and you instinctually feel where it needs to be pointed and how it needs to be adjusted for small movements of current. Of course, large unexpected buffets by the the current will overcome the muscles ability to adjust. But you get the point. Spend every chance you can handling the camera underwater. Eventually your perception will expand to include the camera. Your muscles will do the work without you needing to think about it.
Secondly, in most currents, shooting video with a reef hook is challenging. Instead of flowing with the water, you are being bounced around on the end of a short string. Every eddy in the current is getting transmitted straight into your body and through you into the camera. So, it's preferable not to use a reef hook when shooting video. Get down low and use the natural topography to avoid being blown away e.g. behind a bommie. Of course, don't risk yourself and don't damage marine life. If the currents are too strong, and you must use a reef hook for safety, a springy one connected near your belly is better, find a place where the current is somewhat slowed and smoothed by the bottom topography, then establish an aerodynamic profile so you are flying "hands-free". But, it's not easy.
I know that a lot of "tourist divers" love the flying currents of Komodo but the strong currents are not the more conducive to good video. When I was there last, I specifically planned the trip around half-moon when the currents are milder. Then, for dives in the Straits, I worked with the Dive Manager to plan many of the current-prone dives around slack water. Of course, they have to cater for all customers so you will find yourself flying through Shotgun wondering how to avoid crashing your camera into something...