There are "low hanging fruits" - easier to achieve goals -, and there are super-fruits, milestone-fruits.

Among the most important ones:

-- the long-known Problem of Transparency, applied to the apparent emergent intelligence in NNs. Why does it happen - in detail?

-- then, a Theory of Apparent Intelligence through NNs. Transforming the results achieved into a Science. Which allows to do what we are doing - but in a lean and targeted way.

-- then, a General Theory of Intelligence, that includes the above to go beyond current architectures and get those features of Intelligence we expect and still not have.

The long-term direction we got into must lead to this.

(You note a ponderant detail of the above when you note the importance of explaining the emergence of a World Model from a Language Model.)

If anyone is interested, following Dr Michael Levin's Thoughtforms.life podcast is the cutting edge of where all this previously fuzzy stuff is becoming more concrete. So long as you can tolerate distinguished scientists flailing about as they discuss consciousness and life and developmental biology (and other less-obviously living things, like algorithms) as involving "free lunches" and "ingressing patterns from the platonic realm" :)

Those are the absolutely fascinating parts, and I sincerely hope AI won't get out of control before we're able to tackle some of these.