Don, excellent post. Would you expound on your last paragraph? I have been advised that if an employee comes to me to complain, that I should listen and then ask that employee for their input on how to fix the problem. I expect this is to prevent future frivolous complaints but also to include them in the team effort of providing solutions.
If it is a personality conflict, do you have both people come in at the same time?
What do you mean by "speak truth to power"?
I appreciate any insight you can give.