That is a valid point, it has not been published in any mainstream media, but considering they are not likely to agree with what they are saying, that really proves nothing. I dont know if the paper is published yet, or is online to see, i would very much like to read it before jumping to conclusions though.
I would imagine that since the solar wind is technically an electric current (as the flow of charge, by definition, is an electric current) that an increase of the amount of particles in the solar wind would have the capabiltity of heating the upper atmosphere by electric current heating. The word 'wind' in solar wind has always confused me, you do not say that your kettle is powered by 'wind' flowing through your wires, you call it an electric current. Also the amount of particles in the solar wind does not neccisarily correspond to the light output, or heat output, of the sun, as sometimes the solar wind stops completely. It has stopped for two entire days before; (NASA - The day the solar wind stopped
) So if their is a relationship between the amount of electric power in the solar wind and the temparature of the Earth, its going to be very complex. But I think that variation in the suns output is a definate conteder for GW, although there are obviously many other factors that influence it aswell.