I haven't heard of 'dissociative dreaming' before.

I'm not sure how many people remember having dreams with plots and protagonists etc either.

Most people don't remember dream episodes. You can get better at them by keeping a dream diary, though.

Can you give an example of some kind of dream where there was an 'ah ha' moment?

Freud thought there was a mental structure that not only made up plots etc for the other mental structure to 'watch' but the mental structure also engaged in this elaborate conceilment so that the real urges and desires etc were hidden under layers of symbolism...

I think most people think of this as metaphoric these days. But that being said, dreams are fairly interesting huh :-)