Looks like some people don't know what the thread is all about.
High numbers =/= Good AI. We are talking about 200 SMART enemies at once (they will think logically), not just stupid NPCs with 2 objectives (attack and walk).
1000 stupid enemies are useless against 50 smart enemies.
200 smart enemies will use the engine and hardware much more than 800 stupid characters. However, 200 enemies at once with good AI is impossible in my opinion (for a console). I will believe it when I see it.