You might be:
I am a person known throughout the world,
And yet my accomplishments that are remembered are like some cosmic joke
Despite conquering almost all of continental Europe, there are now a lot of jokes about the French surrendering. Also there are a lot of jokes about Napoleon's height (thanks Amoz!)
I change a piece of clothing just one time!
And so I lost the war.
There is the hypothesis that a change in buttons corresponded to Napoleon losing the war against Russia
My last battle,
Why did it have to be named what it is?
"Waterloo" has become synonymous with being defeated badly.
I feel like God is taunting me,
From above his empire of love.
There is a book called Empire Of Love about the French Empire in the Pacific Ocean. Those colonies were established after Napoleon was deposed.
I was never murdered,
but I might as well have been.
For my fate is the same regardless.
He was exiled to St. Helena, where he couldn't affect change in the world until died. There were rumours that he was poisoned by arsenic, but it, might have just been in the wallpaper
I will never be the most atrocious person,
as that title is saved for another.
Napoleon's legacy is highly controversial and there are some who would call him a tyrant and dictator and render him personally responsible for the over 2 million dpeople who died during his conquests. However, there have been far worse people in history.