New Phantom pilot here but as a commercial helicopter pilot I felt like I should chime in here with some rotorcraft aerodynamics and why coming straight down, especially trying to do it faster, is a bad idea. I see the term vortex ring state (VRS) used a lot here and in this case it is spot on. In manned helos we typically refer to it as settling with power instead of VRS but they are same aerodynamic phenomenon. We call it settling with power because that's exactly what happens to you. The MORE power you apply, the faster your UNCONTROLLED descent becomes, which is somewhat counterintuitive.
As an example, when we set up settling with power (VRS) recovery demos, the helo is put in a stable hover at altitude and a slow vertical descent is started. Unless there is a significant wind you will usually see an accelerating decent rate develop almost immediately. We then increase collective (power), which is the instinctive response for a pilot to correct the descent, and then see the descent rate accelerate dramatically thus aggravating the situation. Recovery is executed by lowering the collective (power), which again is counterintuitive, and flying out of it with forward cyclic (moving forward). This is why "big helicopter" pilots avoid vertical descents to land (aka hover down landings) if at all possible. Even a small forward movement dramatically reduces the chance of descending within your own downwash.
As for the Phantom, I understand there are times when you need to get down in a hurry. I think the quad copter design may be somewhat less prone to settling with power than a single rotor system. However, once you're in it recognition and recovery will be more difficult, especially since you aren't sitting in it to feel it coming. Even with the 2m/s descent restriction a straight down descent is asking for trouble, particularly if the air is still.
Since I'm new to the Phantom I can't speak to the methods of getting around the descent restrictions. Regardless, some forward movement through the air during descent will always be safer and more stable. The faster the descent rate, the more important it becomes. Notice I said forward movement through the air. Landing with a tail wind would cancel out your forward movement...which is another thing helo pilots don't do, land down wind.
Hope all this helps.