Critical theories are useful as inspiration to take a systems-level approach and to question one's assumptions. I'm not sure beyond that that they are fit for any purpose unless they abandon some key tenets of what it means to be a critical theory (e.g. those that prevent accumulation of knowledge).
Written by Rex Kerr
One who rejoices when everything is made as simple as possible, but no simpler. Sayer of things that may be wrong, but not so bad that they're not even wrong.