I concur. To predict, is everything there is about intelligence, really.
If a program could predict what I am going to type in here, it would be as intelligent as I am. At least in this domain. It could post instead of me.
But the same goes for every other domain. To predict every action of an intelligent agent, is to be as intelligent as he is.
I don't see a case, where this symmetry breaks down.
EDIT: But this is an old idea. Decades old, nothing very new.
You're talking about predicting the actions of an intelligent agent.
LeCun is talking about predicting the environment. These are two different concepts.
Yann LeCun, now of Facebook, was interviewed by The Register. It is interesting that his view of AI is apparently that of a prediction tool:
"In some ways you could say intelligence is all about prediction," he explained. "What you can identify in intelligence is it can predict what is going to happen in the world with more accuracy and more time horizon than others."
rather than of a world optimizer. This is not very surprising, given his background in handwriting and image recognition. This "AI as intelligence augmentation" view appears to be prevalent among the AI researchers in general.