Before we go there, though, Kojima offered up an apology for the jungle in Snake Eater: "looks more like your backyard than a jungle," he joked, then apologized to the audience in Japanese for not letting koalas be an edible food source in the game. Would koalas even taste good? They'd probably taste like what they eat -- eucalyptus leaves. Anyway, on to MGS4 not-so-news.
In line with the rest of his speech on innovating gameplay, he and his team knew that they "exhausted the concept of the space, so why not create a situation, rather then a place where Snake had to sneak in" and decided on a battlezone. He explained the possibilities of the battlefield setting -- how there are two sides fighting and one isn't necessarily Snake's enemy, moral ambiguities, et cetera. Then he showed the latest, but already viewed by many, trailer for the game. So, nothing new on the game, but it's nice to read about how Kojima has evolved the franchise across time.
[update: changed the koala's dietary properties to eucalyptus leaves...]