Visual impacts are pretty much universally considered in developing environmental impact statements for wind farm projects, and typically draw significant public comment. A draft EIS will typically include renderings showing what the project would look like from certain vantage points, both at night and during the day, and will consider alternative locations to minimize visual impacts. It's also common to consider visual impacts not only during operation, but during the construction phase as well.
For example, here's a Final EIS for a project off Cape Cod: https://www.energy.gov/sites/prod/files/DOE-EIS-0470-Cape_Wind_FEIS_2012.pdf
I haven't seen anyone argue that the visual impacts are not worth considering due to the fact that the turbines produce energy without burning fossil fuels. To the contrary, sites are generally selected to minimize visual impacts.
What! You sayin' that those aren't alien invaders? I'm all for clean power, and the 4 turbines on the ridge here aren't too bad. But a huge farm of 'em would be ugly, to be sure. Until the Spruces in the foreground of the local ridge grew a bit and started hiding the red lights from my bedroom window view, they did in fact remind me of some wierd goings on. Helicopter night logging, without spotlights, maybe? Ha! Now, I can barely see them, and they don't bother me. But there's only 4 of 'em.
I'm trying to think of a way to generate and transmit electricity that is both silent and invisible, and I'm coming up empty-handed.
Invisible they are not. Follow the thousands of miles of transmission towers and lines in place, planned, and being built to transport all that warm and fuzzy green energy in order to locate the bladed skyscrapers. Landscape destruction on steroids.
"To those devoid of imagination a blank place on the map is a useless waste; to others, the most valuable part." – Aldo Leopold
Coal fired plants have a fairly small footprint....but they really put out the particulate stuff. We see it as haze.
Natural gas has a fairly small site footprint, but you have to run the pipelines there, and if you have been to northern BC that footprint on the landscape is pretty bad in a pristine landscape.