Rooftop mounted VAWTs do a good job of supplementing solar. The best VAWT designs perform at relatively low wind speeds. They do not need to compete with large systems mounted high in the air. You do not need a big high voltage grid when you have batteries for each home or group of homes.
Maybe, but not until the distant future.
We do not have the battery technology to make micro-grids feasible for the USA at large (much less the world). In fact, we don't even have enough known lead and/or lithium to build batteries to do this with today's technology.
Here's a good read on the challenges: http://physics.ucsd.edu/do-the-math/2011/08/nation-sized-bat...
That article is outdated. Its basing figures on an older technology in lead-acid versus Lithium and battery manufacturing has started exploding since then.
He also assumes the same level of inefficiency. With the technologies and policies in my plan, the U.S. can easily be 8 times more efficient.
Plus, for wind to work well you also need a wide geographic area to even out some of the intermittency. That requires a big high voltage grid.