He should not have been murdered in a Russian prison. But if he would have somehow become the ruler of Russia, he would have had to been ruthless or be toppled by someone else. The system in Russia can't be changed by one man on the top. That's like imagining a mafia could suddenly be transformed into a an open and democratic organization.
Assuming anyone wants to change it to begin with. You know the 5 monkeys experiment? In reality, russia is simply a large scale version of it - "this is how it is and the way it's always been".