In the distant future I believe that's the plan. If you look back through the News posts, you'll find one where Andy outlines his plan for annual seasons that last half the year and how new content will be delivered through those seasons. December 2019 we got Dawn of Light with the new Light element deck. Andy has said he isn't adding a new element this year, but maybe there will be an option for a new element in the future.
I think a low number of elements is ideal for this type of game. I think it would get quite hard to learn with much more than 4 or 5 elements. Maybe after a few more seasons there could be a extra layers of elements or something. Like Ancient Nature, Radiant Light, Utter Darkness or Bustling Metropolis. That would keep the core elements the same and maybe these enhanced elements would add a few extra cards to each deck. I don't know if there would be any benefit to this added complexity, however.
Sounds reasonable. I guess I'm just used to 6 elements minimum games.
Would be nice if, based on the first two elements chosen, you get a hybrid card.