Besides transmission issues, what about land use? I mean, what will we eat if all our agricultural land is covered by wind turbines? It is a nice mental exercise to cover all the world's non-aquatic, non-forested, non-urban, and non-polar land with wind turbines, but do wind turbines really integrate well with all the other rural land uses (particularly agriculture) that we have?
It seems to me that researching improved transmission efficiencies and putting wind turbines in the ocean and polar regions (and solar in the deserts) would be a better solution. This is particularly the case as population expands, and previously rural areas become more developed.