sims three would be really cool if you could have pets like in sims 3. and you could have dogs and take them for walks and play frisbee on the beach... or a dog beach and stuff. there could be like an animal hospital if they get sick or something like a humane society to adopt pets. also i think there should be some kind of stroller for your toddlers and babys so you can walk them around the block and then let them out to play at a park or something. also if anyone will read this, hot tubs would be a nice extra
not to mention weather would also be nice, with an option of rain coats and umbrellas. and squirrels and random animals that can live in your trees.
oh also with pets, it would be cool if you can change their personality traits like the sims. like a paranoid dog or a timid dog or a hyper cat, something like that.
oh and while i have your attention it would be cool if you could go into actual working buildings and see your sims work. if you a waiter bring food to tables or a surgeon watch them save a life.

these are just some of my ideas, what are some of yours