1. Wishes in the "Un-promised Box", when achieved should pay out in LTR!
... I find it rather frustrating when I'm unable to earn enough LTRs for my sims. Their promise box is full with wants that are going to take some time to achieve, while easier wishes go through the un-promised window and if are granted, they're worthless. How is this really fair? If it's there isn't it a wish, so even if it's not promised shouldn't the sim get the rewards for achieving it?
2. Add Memories
... This is a feature I loved with Sims 2 and am really missing with Sims 3. I love being able to go back and see those special moments. What would be awesome if we got to pick and choose which memories we'd like to save. Growing up, special parties, getting married, etc. It would be a feature that could be turned on or off perhaps? I know taking pictures with the phone or a camera can also "save" these memories, but sometimes we don't have the photo options, or we didn't get the opportunity to take the picture. It'd be nice to be able to go back and see these moments again.
3. Photo Album
... I'd love to be able to start a photo album for my sims, a place where taking pictures with either their camera, or the camera option in game. Even if we can't add comments, it would still be awesome to have a place to keep multiple pictures. My sims only have so much wall space!
... It's in the Official game guide as a cheat to add points to your LTR, and yet it's never worked. It would be nice to have this a working cheat!
I'll add more as I think of them, but feel free to add your own to the list.