Multiple fighting arenas, they already have the layout for two of these on New Chuchunka and Aya, just open them up for players to enter.
Return to Habitat 7 - identify that the thunderstorms have a 'dry season' and get to look into some of the other Remnant sites that you visited but couldn't fully explore
Obviously large expansion for Quarians that involves more stuff on Nexus too
Perhaps show the growth of the Nexus as it moves on to wave 2
Cosmetic upgrades .ie. more Nomad skins, more casual clothing, squadmate outfits!
And finally some kind of bridging content probably related to the benefactor maybe involving ER