My perfect game would have the best of Sims 2 thru 4. All the age groups, interactions, traits, Aspirations (Sims 2-3), Wants/Fears (Sims 2), Personality Traits (Sims 2-4), Chemistry/Attraction (Sims 2), CAS (Sims 2-4), Community and House lots (Sims 2) and Memories (Sims 2). Not going to go into too much detail on these, otherwise I would be here all night talking about what I want LOL
I would like no loading screens (since I will likely always be playing on a midrange laptop without the best graphics card).
Also, get rid of all rabbit hole locations. I would like to see what my Sims are doing on every lot they visit.
I pretty much agree with what has been said previously. I just wanted to add a few things I would like to see in a perfect (to me, anyway) Sims game.