I would love it if the other Sims in a neighbourhood were controlled by other players. That would make the game a whole lot more interesting. Imagine you make a Sim and their love interest were controlled by someone else? I know there are about a million things that could go wrong with that but it would a new dynamic to the game which would make it MUCH more addictive imo.
And I love Sims 2 and 3 equally, am I weird?