It's true, N did leave to another region at the end. However, when he returns in B2W2 (we all know he will), I don't think he's going to be on the side of Team Plasma. Ghetsis betrayed him, used him, and I don't think N is the type of person who's just going to forgive and forget that so easily, regardless of the time jump. I think N's going to be on his own with his own personal agenda.
What I find interesting about Team Plasma in B2W2 is that there are like two sides. The white uniform and the black uniform. Now unless their clothes are specific to each version, I'm betting that Team Plasma may be split into two teams. That's just my theory anyway. I also think it's possible Akuroma may be on the side of the Black Team Plasma going against the White Team Plasma's continuous plan from Black and White. Which, I assume the old Team Plasma would be lead by the Seven Sages and Ghetsis, who will reveal himself later near the end, or so my mind is telling me.