Somehow I doubt EA will have to push them to make more Mass Effect. Bioware invested a lot of time and money into creating their own IPs so there's no way they'd just abandon them so soon. They'll stop making Mass Effect games only when they cease to be profitable...which may be right after the next game whatever that may be. Who knows.
Personally I'm just interested to see where they intend to go with it since ME3's ending(s) leaves them with very narrow options as to the state of the galaxy. If they set the game post ME3, they're be forced to pick a "canon" ending, which lets be honest can only either be destroy or control...probably the latter since the former rather undermines their whole (self contradictory) premise from the original trilogy that organics will ALWAYS create synthetics that ALWAYS destroy them. Though it's probably Bioware's preferred ending, synthesis is just not workable in the long run as it rather precludes all possibilities for conflict and drama. Pretty stagnant ground in storytelling terms. Even so, control has the slight problem that the reapers are still around, meaning any big galactic threat will have to include some contrived reason why AI-Shep's attack squids can't/won't deal with it themselves.
Sure they could set the next game somewhere between humanity's first contact with the turians and the events of Mass Effect 1 (b/c though it'd be cool, I can't see them doing a game sans humans), but that is even more limiting in terms of scope and--depending on what kind of story they choose to tell--they'd quickly run out of times and places for their games to exist.