A dating pack is definitely in order. Aside from an attraction system, the number one thing that this game needs is the ability to have one-sided relationships.
It annoys me so much that romantic feelings in TS4 are always, always reciprocated and in equal measure. In other words, each Sim doesn't have an individual romantic (or even friendship) meter. They share their meters with whichever Sim is in question. If Sim A loves Sim B, Sim B, by nature of the programming, also loves Sim A. Sim C thinks Sim D is there bestest bud ever. Sim D automatically feels the same.
I know that some will dislike the use of this word, but I'm calling it as I see it: that is shoddy decision-making with subsequent shoddy programming. Heck, it's lazy and so fifteen years ago! It's time that romantic relationships became deeper and more nuanced in TS4. Or, at the very least, catch up with the games that were released years ago.
TS4 has so far to go and, in my opinion, will always come up short because previous games did so many things better on the simulation side. I buy these games for the simulation, the graphic fidelity is only going to go so far.