I wasn't expecting much, but read the article anyway and I was pleasantly surprised by the stuff they got right. And even more pissed off by the stuff they got wrong.
Yes, switching out windings at low generator speeds will tend to make it more efficient. This applies to PM machines, and could probably apply to induction machines too (though with some other issues).
However, there are many, many other things limiting the power captured from the wind besides the generator efficiency. Blade efficiency tends to drop at low wind speeds, as does the total power available from the wind (it goes with the wind speed CUBED). I'm skeptical that improving the generator efficiency will result in much change in the overall efficiency.
Also, they fail to discuss cost. Very, very few wind turbines today use permanent magnet generators. Why? They're expensive, and you need power electronics rated to the full power of the generator (say, 2 MW) to rectify the output and invert it back to AC. Power electronics of that scale are expensive too. Instead, most wind turbines use induction generators (cheaper) with power electronics controlling only the rotor currents (rated to about 30% of the total turbine nameplate rating). Until they deal with the cost issue, it's really just another trick to get a little more energy out of a PM generator.
And, speaking of energy, the author of that article needs to be locked in a room and made to write "power != energy" on the blackboard a thousand times.