The problem with private offices for developers, which is how I read #6 as advocating, is that it separates developers and cuts down communication. If you're a developer you're generally working with a team, and this has no team component. Joel got it right IMO: http://www.joelonsoftware.com/items/2008/12/29.html
EDIT: Something came up and I didn't get to finish my thoughts on this topic. You need to be able to strike a compromise between privacy and for focus, and openness for communication and making sure that the team has a single, unified vision. Joel does that well by giving each developer an office with glass walls. Everyone is approachable, and you can see what they are doing, pop in and ask a question, etc... But the distractions of office noise and chatter are cut out.