Sewing might be a bit too similar to knitting, I feel like if it's added, maybe some renaming should be done to have it use the same progression.
A pool table would certainly fit in and is long overdue in this instalment considering all previous games had it in the base game.
Mainly I would prefer to keep these free time things restricted to stuff that can be done around the house, those kind of hobbies.
More video games could be added, EA could use more of their own library instead of just their boring sport and race games. Let my sims play Mass Effect and Dragon Age!
Of Sims 2 free time I really liked being able to fix up an old car, so I think that should return alongside with cars which are also long overdue.
It could have a bit more customisation to it as well for the cars made.
It could also include additional rockets and some changes made to the existing rockets to give them some added customisation as well and being able to pick your space suit.
Since we already have an ice skating ring, I would suggest adding a new one with goals and let sims play ice hockey. (does come with risk of injury.)
Drums should also be added alongside with new versions of existing instruments, and of course an electric guitar which is also still missing.
Ballet is a good idea, but I think they should add several dances. Sims should become able to actually dance with another sim again, holding them, not just awkwardly dancing beside them. The Tango, Jive, Cha-Cha and slow waltz could maybe be added too, able to learn it on a dance floor.
Model building could also be a new hobby maybe, some stuff sims have to put together before being able to put it on display, each of these collections could have their own table your sim can keep adding to, adding more interactivity.
Model trains could be one thing for this, sims could add to the landscape over time, buy a tunnel, put together the train, make the train longer, etc.
Could be a star wars table too since they have the license, could have models of an AT-AT, death star, millenium falcon and all the most popular models sims can put together to add to it.
Maybe one with a large victorian doll house as well that sims could work on filling the rooms and decorating it and all that.
More board games for sims to play could be fun too, maybe being able to play it lounging around a coffee table too. Maybe they could even play D&D or some sort of sims version of that like Wonders and Wyverns.
