I think there should be a "family" tab in the relationship panel, so you can easily see how close your Sim is to all their living relatives.
Apart from that, there's one minor thing I'd like: a hairstyle like that one from the Cats and Dogs pack (the only medium-length one), but without cat ears. We have different versions of other hairstyles, with and without multicoloured streaks, so I think that's reasonable. I don't have anything against the cat ears, just so you know. I just want some of my Sims to have the actual hair by itself.