you're right, it's kind of sad, but 40000 seats is good. That's the only way you can create atmosphere, and you can play in a full stadium. Plus, there's an economic aspect to that. Having less seats results in other price-categories, more season-tickets etc etc. So that was the only possible way and they did pretty well i'd say.
That concept with that whole area of businesses, offices, etc strikes me though. i kinda like it and i like the idea that we are bringing up somthing unseen 'til today