I find that restrictions not only don't kill creative work, they enable it. Measuring anything makes you consider constraints, which helps foster better creativity - at least for me, and I see the same in others as well.

Restrictions have dimensions. I have enjoyed working in highly cooperative situations where we had restrictions of resources and rules but no restrictions in terms of allowing us to find solutions. Infact those solutions were celebrated by my manager who had to work within the confines of rules and resources defined for him. It was great fun.