1. Running.
2. A mobile camera like in TS2 and TS3!!!!!!!!! Please!
3. More interactions for children. Where's the family kisses, the hugs?
4. More unique animations for different interactions, less recycling. More interactions in general - lifting them from TS3 is fine!
5. Being able to build and buy anywhere in the kingdom.
6. Some option to age kids up into townies or have heroes retire and also become townies, or playable sims that cannot be selected for quests anymore.
7. Some option for natural death. Right now anything to "remove" Sims from the Kingdom permanently involves either suicide or murder. There isn't even a testingcheats option to infect a sim with the plague or anything.
8. Non-default children's faces.
9. More cheat options, period.
So there. A list of fairly minor additions that shouldn't be too hard to implement. I'd really hope to see such changes in the future, to make a great but flawed game amazing for me.