Doesn't that work? (honest question, I don't use XCode that much):
defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool false defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool false
But seriously, I hadn't really known about Xcode plugins, despite using it a lot of the time. I'd used a few but they were annoying to find and install. This is perfect and with an "Xcode Plugin" template available in it, I look forward to many more plugins emerging soon!