Have you never watched E3 before? Besides Nintendo, who usually only shows things super close to release, everyone is all about empty promises. Hell, last year we were told Halo 5 was coming this year.
Seems a bit too soon considering it was just announced last year, and DICE have multiple other projects in the works right now. DICE need to take their time and make sure its done right. I couldn't handle another BF4 incident with my beloved Battlefront.
I think they know they can't get away with another tease this year. My bet is that we'll get a similar demo to the BF4 MP one last year, maybe with the big setpiece moment being an AT-AT getting taken down or something.