Add quests / story mode to the game

I think it's clear from Strangerville that the Gurus are not writers, so stories from them are likely not going to be any better. And the effect of a story may be lost in the game because events your Sim must complete are summed up as to-do lists in the top left corner. If anything, asssuming TS5 is worth its salt and goes back to the roots of what made the Sims great in the first place (borrowing and improving upon many elements in TS2, TS3, and TS4, but mostly the first two) like other games have been doing successfully (Resident Evil, Devil May Cry, Soul Calibur), then a "Create Your Own Story" mode (as in something optional, just in case you, reader, are like the posters above who thought the OP meant to replace the sandbox gameplay) could... possibly work.

But honestly, I have major doubts for any of the above to become reality, so.