It is clear that Filner is dealing from a weak hand; so he throws a tantrum. But his tantrum is exactly the response of a someone who feels powerless; this makes him look weak. His strategy on the hotel tax is also incoherent. He claims that it is illegal, but then makes a demand for a bigger cut before he will sign off on a contract to use the proceeds to fund a tourism campaign. If the tax is illegal, then the city is not going to get its cut for public safety. And if the tax is legal, then using the money for public safety will make it illegal. I don't see Filner's play in this, unless he is just grandstanding. Ultimately, the public judges the mayor on results. Starting vendettas is not typically the way to achieve positive results.
Maybe he just has anger management issues. I'm thinking its only 50/50 that he finishes out his term.