It's pretty much a done deal that the new Mass Effect - whichstubbornly won't call Mass Effect '4' - will have an online multiplayer side of things. This is hardly surprising since Mass Effect 3 introduced a successful formula.
The multiplayer wasn't directly connected to Mass Effect 3's main campaign, although it could have a slight impact on 'readiness'. The same sort of online component cropped up in Dragon Age: Inquisition.
Co-op multiplayer proved a surprise hit for the sci-fi series, and is trying to do the same now with Dragon Age. The studio has already said that the new Mass Effect won't be taking Inquisition's lead in designing the RPG, explaining they have to find their own way.
Mass Effect 3's co-op multiplayer had us fighting waves upon waves of Cerberus, Collector and Reaper forces. We took the role of soldiers in service to the Alliance, fighting to gain and hold control of strategic locations across the Milky Way. How will multiplayer fit now in the single-player RPG?
Maybe we could have some MAKO races on an asteroid hurtling toward a black hole?! The next Mass Effect is due some time in the future, and hopefully this year's E3 will have something for us.
BioWare's Edmonton team is also working on a new IP.