I think it’s possible Regina might die and then next season, we get a new villain.
I think its very possible that Regina may die..but may be back as the EQ still next season. She has basically run through her story arc in Storybrooke and with the breaking of the curse there wouldn’t be much for that character I think.
Also, Malificent is coming back in the finale…so, maybe we have a new female villain to focus on for season 2?