Then it's not the question of whether it'll be possible, but what makes you think you can mass up even up to 500 players even once the game is out for a while? The levels for that would have to be enormous, and what if you can't get 500(Or even more) players on a constant basis, what then? Are 40 players going to run 2 kilometers in order to meet each other?
Of course, there'll be smaller game modes(I hope so) to take care of the faster paced and smaller level environments, but also for lower player counts.
Just a question.