Since this is coming out for Wii, The remote should have plenty of interesting functions (Fishing, Mini-games, etc.)
Wi-Fi should let anyone at anytime visit your town and visa versa (assuming you opened your gates)
There should be some form of cooking or alchemy or crafting of somekind.
grow crops, trees, and bushes and flowers of many different varieties.
Furniture that can hang on walls
Bigger Town with many different looking areas.
There should be a Universal area, in which players connect to wifi and can travel to a number of different areas where no one can live, but there are still things to do. (A mall, amusement park of sorts, maybe a boardwalk, use your imagination)
snowball fights! You should be able to throw things. this would especially be cool with the wii-remote.
More... charming scenery and weather and things like that...
Much needed and much deserved graphic upgrade. It can have the same look to it, but everything should be a lot more detaild and rich.
More things to collect. Not just more bugs or more furniture... maybe collect stamps! or minerals. Maybe mining should be in this game or something...
More room for More Characters!!
Interactive furniture that can actually... do stuff!
UFOs!
Each character should be completely unique, with different likes, dislikes. If they put cooking in this, imagine the possibilities!
Anyone disagree with any of that?
If you have you're own ideas please share!!