Maikalan

My suggestion for a Sims feature would be to combine 13DS and The Exquisite Corps.

My pitch: Abby acts as the knowledgeable 'Commander' while Dan, Alex and Vinny play. Each participant picks two people to add to the house (celebrities, game characters, staff members, anyone really) for a total of 8 sims.
Then each player picks a sim and a late game goal for them. Perhaps they get married and have a family, advance in a certain career, accrue money and buy a house, etc. I'd trust Abby to determine suitable goals. If that's too easy it could be multiple sims with multiple goals each.
Each player then takes turns trying to advance their own goals while sabotaging the others. First player to complete their goals wins.
Caveat being one can't make other goals impossible. No killing other sims, no locking them in a doorless room. I trust Vinny and Alex to be good sports about this and hopefully Abby can reign in Dan's bullshit.

I'd like a feature that leaves more room to explore what The Sims is capable of while fulfilling the "what the hell happened here" promise of Exquisite Corps.
In any case: more Sims.