If you include Sir Isaac Newton in a case against employing geniuses, your case is pretty thin.
Why? From all I have read about Newton, he would have been the employee from hell. A genius as a mathematician and physicist, yes; but a terrible employee.
[NB For a fictionalized, but hugely entertaining, account of the relevant time in history I can recommend Neal Stephenson's wonderful "Baroque Cycle" - Newton is a major character.]