Wouldn't it be cool to play a family from sims 3 that evolves to sims 2 and ends up in sims 3 to go in sims 4?
For the 20th anniversary of the sims, there could be an export option to transition your next generation in the next game... Or to put them back.
You could also make prequel of your sims, by bringing them from sims 1 or 2 to sims 3...
You could even play their ancestors: sims medieval! (They could have a perk: I'm a descendant from a king, I start with more money, a bard, I have music skill, a blacksmith, I'm handy, a magician, I have supernatural powers, etc.)
If all the sims were on origin, it would be easier to run them all in parallel.
There could also be a complex genealogical tree system imbedded.
Ah, I wish.
Played Sims 1 when I was a teen... Still playing Sims...
Learn more about my Polar Bear (Sims 4):
Grisby legacy in Riverview (Sims 3):