Leibniz more than any other philosopher gets the short end of the stick, doesn't he? The man was a genius. He invented binary code, and so many other things. He had all kinds of interesting philosophical ideas. An intellectual powerhouse by any measure.
But some pseudonymous prick makes fun of him for one eccentric (though in my view, surprisingly defensible) belief, and that's what he's remembered for. "Oh, he believed we live in the best of all possible worlds, what an idiot!" What did deist Voltaire ever do other than be the enlightenment, deist equivalent of Christopher Hitchens? Screw him and his poetry, on this count.
Mind you, Voltaire is leaps and bounds beyond the gnus who worship him. But he'll always have a demerit for heaping scorn on a man who was his better.