Giving the players their creative freedom back
i would make the game easier to mod and create CC for
and allow players to make any hair, clothing, items accessories and whatnot
at any point in the game. The sim designs
would be simple, but pleasing to the eye so that they aren't
limited to high powered machines. There would be more family options, group activities and
before the game's released, a demo would be sent to all selected players for a short amount of time
and based on their feedback, we make changes to the game, and maybe add or minus some things
about the overall HUD and sims that a lot like or dont like.

At least, thats how i'd design it

Take Sunlit Tides for example. They could have saved it for the Island Paradise world. Or Late Night and Showtime. Why can't they make expansions to expand on other expansions so they are actual EXPANSIONS! >.<

Above all, the game needs to ship in a working condition. These games have been messy since the beginning one (Sims 1) and neither Maxis nor EA have been very responsive to consumers. Please build a product that does not have so many design flaws. Create something that works and is reasonably easy to use and fix and leave it so that it can be played our way, not by some prescribed design.