Other than that the 2nd ed material provides plentiful setting material for 3rd ed in terms of people, places, plots and ideas? None. But then I was merely answering your question:
The reason 3rd ed has focused more on getting crunch out before fluff is that while many GMs and players will have some 2nd ed material available to use and build on in terms of 'fluff' - they have no models for the numbers in 3rd ed. Therefore - the greater need is answered first.
But how does that relate to 3e?