What do you expect from this conference E3 in relation to The Elder Scrolls Online ?
Rumours are that Bethseda has something big to announce (I believe the first and only time they did their own E3 presentation was to announce fallout 4), so it could be the first teasers of the next TES game.
In terms of ESO, I find it suspicious that ZOS have been so explicitly tight-lipped about what is coming next. If you remember the video/transcript of the pax talk, a lot of what they said was about how they couldn't say...
I hope it means they want to wow us with something to get the community excited, and my best guess would be to announce a really interesting take on player housing AND small-scale PVP, although not necessarily in the same DLC.