Learning all the complexity at once is very, very painful. It is my least favorite thing about playing board games. However, once you play a board game often enough it can become a bit boring without more surface complexity unless you really find pleasure in playing it like it is a full time job. (This is why I don't ever think it is worth it to become great at chess... too much effort for too little reward.)

I think expansions are the sweet spot. Produce a base game, then add complexity with expansions.