Honestly in Sims 4, if they were to make a Seasons pack I’m almost certain that they’re going to focus more so on the effects and consequences of weather rather than add seasonal realated activities. So possible things like alternative electricity options, more ways for things to go wrong in your house like leaky roofs, flooded basements, power outages, different weather behaviour in the different worlds so each world has a unique weather experience, weather affecting the mood of the Sims, weather affecting the development of skills, etc. I’m sure there would still be things like build a snow man/igloo, have a snow ball fight, rake leaves, and possibly some new things mow the lawn, shovel driveway (if cars are in the game by this point), etc. But bonus things like snow boarding and skating I think would be left to another pack this time around.