Light and Height

One common argument against tall buildings is that they block out light, creating shadows that block the sun.  But as I was walking down Avenue of the Americas (one of Midtown Manhattan's most skyscraper-oriented streets) I saw plenty of sun- just not on my side of the street.  What was going on?

I was walking on the east side of the street, where most buildings were 5-20 stories.  On that side, some combination of skyscrapers and the sun's natural direction created shade.  By contrast, the west side of the street, where all the skyscrapers are, was quite sunny.  So this particular street had a nice balance of sun and shade- if you wanted shade you could go to the east side of the street, and if you wanted sun you could just cross the street.

It therefore seems to me that if city planners wanted pedestrians to be able to choose between sun and shade, it could impose height limits on only one side of each street; the side across from the skyscrapers could be shady, and the skyscraper side would normally be sunnier.  On the other hand, this sort of regulation does mean that the urban fabric is less consistent; instead of causing a neighborhood to have a coherent look, setting different rules for different sides of the street would create a divergence between two sides of a street.  Is this a bad thing?  I'm not sure.