Du Burns wasn't even elected Mayor, so I don't think he deserves a statue. Kurt Schmoke is more deserving of a statue, IMHO, since the people actually chose him. But I think it should be erected after his death -- I disagree with statues of those who are still alive being displayed.
I'm also not a fan of the Schaefer statue. Too soon, and there are negative incidents from his years as comptroller that are still relatively fresh in people's memories. He should have ended his political career after he left the Governor's office.