-Big price drop would make them look so bad (but I guess if they remove Kinect it wouldn't look like they just admitted defeat).
-unless they are absolute ninjas at hiding internal stuff, they can't have many new ips outside of Halo,Gears and Fable being developed, since we know what most of their studios are doing already.
-Rare is irrelevant at this point, they are a Kinect games studio.
Things that could help their E3 presentation:
-Sunset Overdrive or Quantum Break gameplay that looks absolutely great.
-Announcement of money-hated game. This one is tricky, if its just something like hiring a third-party developer to make a new IP it won't make a big splash, there aren't many third party big franchises out there that it would be reasonable for them to money-hat with the smaller install base Xbone currently have so the best bet would be for them to reboot or remake some old franchise.
-Announcing that they formed/bought new studios and show the games they are working on.
-Some new tech (hard to convince people to buy an add-on after forcing them to get the Kinect).
They are in a very bad position, Sony has much more cards to play at E3:
-We don't know what Bend, Media Molecule, Quantic Dream, London, Guerrilla Cambridge, Santa Monica and Japan Studio are working on.
-Project Morpheus game announcements and demonstration on the on the show floor (OR steals the spotlight at everywhere they show up, the same might happen with Morpheus).
-More information on games like Uncharted 4, The Order, Deep Down, Lily Bergamo, Rime, etc.
-Ports of TLoU, Journey, Uncharted...
-PS4 indies.
-Vita related announcement and reveals like Gravity Rush 2, indie ports(Papers Please, Mincraft,etc), memory card price drop,etc.
-PlayStation Now and PlayStation IPTV.
-Crazy stuff like The Last Guardian, Agent, Crash, Shenmue.