More than enough space. And you can't just say "Nope, won't work. Nope. NO WAY," without any evidence to back it up. We already know that War Machine works with five people. How do we know this? Gears of War 2 War Machine. Yes, it sucked terribly in that game, but not for the reason of number of players in the game. It was bad because of how glitchy/buggy the ledges were. Half the time I would get stuck on the edge, or I would lag back on top of it, etc, things like that.
It's much better in GOW3 and most likely Judgement. I see no reason to not bring this map back.