Damn man. Hate of halo is strong with you.
If you read the Bungie interview on VGchartz homepage you will find out that Halo ODST is as long as Halo 3 if not longer if you take your time with the story.
Also last time I checked this game will have 4 player split screen coop. Anyone that is not a graphics whore will accept a 4 payer coop trade off for lower resolution. Besides graphics have shown to not matter as much as gameplay this gen. Only a few die hards are left putting slow motion Killzone 2 gifs in their sig...rest of us don't really care.
And if one is a die hard graphics whore...WTH would you have a console? PS3 or 360...