He would not become a tyrant!! Take kingdom come for example, all the Daily planet staff members were killed by the joker which included Lois but Superman still continued his fight for justice, mostly his whole city turned against him when he said magog should be punished for killing the joker but he chose to exile 'himself' not the people or magog, he still wouldn't kill magog when he blew up kansas, Superman's home state. Superman is Superman because of the strength of his character and his values not just because of his powers, there are many other kryptonians which have come to earth since but only clark is called Superman.
