I wouldn't just be concerned with the outside. The state of the bathroom makes me think they're not caring for the inside well either. I don't think it's a coincidence they didn't vacuum or mop for the inspection....I wouldn't be surprised if they never do!

If that were my rental I'd be wanting them out sooner rather than later. If they were paying rent consistently is consider giving them a chance to rectify things, but since they're not I think out is the way to go.