I am more skeptical of the financial strength of the GSEs, and believe that we could see substantial problems in that sector.
I would put the GSEs at the top of my list of sources of potentially serious problems. If those problems were realized, they would be a direct result of moral hazard inherent in the current structure of the GSEs.
I'm actually a bit surprised to see a Fed bank President acknowledging any moral hazard. Apparently there's a limit to how far some people will go to ignore the obvious.