^I think a lot of DLC will come. For both versions. They're going to milk this game hard. They could add points and trophies through plenty of different kinds of content.
Just with the way Case Zero was released as an arcade game it sold gangbusters and the very quick announcement of this new Case West I'd lean more toward this being another arcade game to be released probably within a month of Dead Rising 2's release, hopefully as another arcade game as it will definitely achieve the same sales success, perhaps DLC wouldn't be as profitable, who knows.
We'll see though, I wouldn't like buying the game twice, but I love Dead Rising that much so if I had to it'd be worth it for me.