I wonder about the sub-500-kW units: that's not something new, that's where the average turbine was in 1997 or thereabouts. The way I understand it, the trend for the bigger the better was footed in two main reasons: the rise in hub height (stronger and less turbulent and more stable winds higher up) and less impact (visual and road and cable ditch). So sub-500-kW units would appear useful as niche fillers: off-grid supply for a consumer with low demand, sites hemmed in relatively closely by residential areas, and the mountainous sites you mention.

_{*Lunatic*, n.
One whose delusions are out of fashion.}