I have a really hard time believing that Halo 4 is going to be jaw-dropping.
Games like Uncharted 3, God of War 3, Forza 4/GT5, Lords of Shadow; those, those are jaw-dropping. Halo 3, ODST, and Reach were serviceable and best. Poor textures, wonky sub-30fps and sub-720p performance, and jaggies everywhere. Sure, it's more open-world than other games; but that doesn't mean it gets to boost it's ego to be a "good looking game."
That said, this is a new developer that's had lots of time and lots of money to build Halo 4. I'll give it the benefit of the doubt for the time being.