Just try to make a new save file every 1 sim-week and you should be fine. I had the same problem back then. And maybe you have low memory, I have 2G Ram only.
Those little mans are creepy but funny, they are changing postures which is unique and they are annoying at the same time because they keep coming inside the house.
Business Owner or City Life would be fun. We need more business or like a profession which we need to do it manually like in sims 3(e.g fireman, hairstylist)
Well they add new interactions but it still seems lacking. But I get to enjoy the game, so I think it is great from me, not to tell it is only the base game for now.
They should add more sweet things like Goodnight's Kiss, storytelling before bed(for kids), and drunk sims. Though I wish they put back the cameras wherein they can take family photos. I miss that thing from The Sims 3.