I believe that a good part of the market is interested in switching from multiplat to exclusive ps4. I don't think there are going to be a whole lot of developers who move in that direction but we already have several annuncements of exclusive third party games in the last month.
I think MS definitely is going to focus on their own studios. I really doubt they are going to include any multiplat, or timed release exclusive multiplats in their show.
I also believe they said their show was only going to be an hour, so it could just be filled with exclusive first party content.
As I said before, my rpediction for e3 is that ms is going to somehow provide streaming access to all of their games, rather than necessitating a wait in line. If that plays out true, it would only make sense to focus on first party, so that they could have the software available for demoing.
