I dunno, it would depend on how it was done. His mission was to guide humanity through its most turbulent era and make sure it survived. I could see there being a story where he had to do something ruthless in the short term to protect the greater long-term good, akin to "Edith Keeler must die," say. Although I don't know how it was done in Year Five. I lost interest in that after they portrayed Tholians and humans coexisting in an M-class environment without difficulty.
