I have a suggestion. I think that the best way to define local risks is local risk view: right pane will be a project schedule; left pane is risk breakdown structure similar to global risk view. This way it would be possible to define local risks for multiple tasks at the same time.
I think even existing way to define local risks is quite good. I did not have any problem entering risks in the local risk table. I agree, local risk view can be quite useful.