What is numentas biggest limitation?

A"G"I has a G for General. Which I haven’t heard one bit in any Numenta talk.
Numenta wants to copy the cortex and subcorticals to accelerate machine learning. They explicitly say they will leave out IMPORTANT topics like qualia, emotions etc (which i don’t agree).
The thing that holds them back is the thing that holds anyone back: a theory for the brain. How do you get the best features from the brain without going full cargo-cult science? Put a symbol somewhere and abstract away the rest. But abstract away WHAT?