It is not very often that agents terminate properties, since they derive their income from leasing and selling properties. I would have to say that in this case there must be 2 sides to every story. 

I personally have just listed my 10th investment property with Sweeney Estate Agents and have found them to be most professional, dilligent and always act with my best interests at heart. They come highly recommended in my book.

I have a friend who has been a property manager for 10 years in the Sydney property market who says she has only ever terminated 1 property and her reasoning being that the Owners were being unreasonable and couldnt understand the Residential Tenancy Act and guidelines provided by the Agent.

You say in your post that bad Agents should be named in a public regster, in this case maybe there should be a public register for bad landlords????