Should cut a card (instant or sorcery, ideally) to be on track for 200 card cube.  However, would like to add dread return and possibly living end.  Curve looks alright.  Don't sweat any further changes right now.  Do the rest of the cube.  It's possible that artifact or multicolor may be short, and almost certain that land will be low.  So you might end up making each color greater than 26 cards to compensate, while remaining at 200.