@Garnett
Its' a progressive part of HD consoles, improving all the time. More open worlds, better physics, more detail. Everything takes time, but Microsoft & Sony are the ones who will break into this moreover than Nintendo. Microsoft & Sony do try with games such as GTAIV, Fallout 3, Oblivion and others. Maybe technology isn't ready yet, or maybe with the newer games we will see more in the upcoming future. The only open world game I can think of for the Nintendo console is No More Heroes, but it isn't really open world, very limited.