I don't think that there will be too many surprise title announcements at E3, most AAA games seem to get announced or leaked in these weeks leading to the event.
Assassin's Creed, Call of Duty, Star Wars Battlefront, Tony Hawk Proskater and more have already been announced so that PR teams can focus on giving details and demos at E3.
Fallout 4 is all but confirmed.
What I'd like to see:
Last Guardian confirmed for PS4
Fallout 4 gameplay
The unannounced Star Wars game that Amy Henning is on
Cyberpunk 2077 details
Rainbow 6 campaign details
Zelda Wii U in action (NOT offscreen footage)
Nintendo streamlining online accounts and UI
More amiibo functionality
Redesigned Wii U with larger storage or price drop
What I expect to see :
343 finally showing
what's in the box Halo 5 edition Xbone
Wave 6 amiibo lineup