No promises would be broken, no original Lyon boys would be murdered, and no Lyon parents would have to be deeply mourning in the event of a Season 6.
It would be clean, game-changing, and potentially awesome without driving away fans who have a favorite member of the original Lyon family.
Killing off Kingsley would allow Empire to follow through on its promise to kill a Lyon without actually knocking off one of the members of the family that viewers have come to care about for the past five seasons.