I've pulled out the following question and answer from an interview with the originators of the Intense World theory of autism on Wrong Planet, a well-regarded website for and by people with autism.
It explains the key differences between the Intense World theory and older ideas about autism.
Q8. "Unraveling the Paradox of the Autistic Self," by Michael V. Lombardo and Simon Baron-Cohen, states that "neural evidence provides a key clue that an 'egocentric' response in the brain (i.e., Self = Other) is actually the result of an impairment in self-referential coding of information." Do you believe an elusive sense of self is a universal autistic characteristic? Does Intense World Theory account for this impairment?
Answer. Well, we would not agree with their analysis and theory. This is just another theory that is a relic of the theories of mental retardation. It is contaminated by older theories that there is a deficit in the ability of the brain to develop a theory of mind, the ability to see and respect others thoughts feelings and emotions.
This archaic theory has also led to gross misinterpretations of the mirror neuron discoveries. According to the Intense World Theory, autists could actually be seeing much deeper into the minds, thoughts and emotions of themselves and others, which triggers active avoidance and lock down behaviors. It also requires the ability to simulate others as if you where them and to extrapolate to where their thoughts and behaviors are leading them.
Seeing into the minds of others can be extremely disturbing. Even if autists don't feel this is true for themselves it is because their brain has developed strategies to cope with this extreme insight leaving them seemingly isolated.
This theory of a deficit in self-referential coding or theory of egocentricity is also likely to be incorrect for another reason. Self-referential coding is the foundation of human consciousness. To be conscious of yourself and others requires you to have to be able to localize yourself in space and time. If you enter an isolation tank, anesthesia, or deep meditation you can lose track of yourself, where you are, who you are, what time it is.
So impairment in self-referential coding will also mean that autists are barely conscious and living in peaceful state of diffused consciousness (pain is based on a sense of self, locality). It is most likely the exact opposite of autists. They are in an extremely localized state, extremely aware of themselves, extremely aware of others and in a battle for their life to hold back the intensity and pain of it all.