No beating around the bush! This article is a must-read for anyone interested in downtown Seattle livability.
Anton Babadjanov has put together a well-researched article on the trade-offs between tower spacing and livability in the context of natural light levels and its effects on learning performance, productivity, psychological well being, and physiological well being.
Since his research concluded that access to natural light is crucial for people, the question became how to provide it and still accommodate the need for adequate housing. His solution:
Add tower spacing, but only with increased height and FAR limits. In this way, the improved human outcomes of tower spacing outweigh the decreased outcomes of the minimized displacement likely to occur.
Obviously I can't do justice to a nine-page article on this blog post, so read it for yourself. There's a message here that should not be ignored.