Good approach. Making a mortal enemy of the outgoing sysop, or simply his object of scorn, will screw you badly.
Other than to say "you're screwed", the big step is to also ramp up the professionalism and start building a better system governance policy and documentation process. The best way to explain that to management is to ask "Do you fail the Hit By a Bus Test? ".... If your key administrators are hit by a bus, will your systems go dark ?