With how the Zodiac signs worked in Sims 2, I am a bit wary of them in terms of limitations. (At least for those who care for storytelling gameplay or creating Sims of beloved characters.) IRL Zodiac signs are fairly broad where almost anyone can find something in their sign that actually correlates to them. In the Sims, to make the signs have actual relevance there were more specifics and thus limitations. Each sign fell into having a specific range of personality traits. In turn, if you were creating a self Sim or a Sim of a real person, their sign could quite often not match up with real life or at least not with how you perceived them. I always disliked how my sign was presented because a lot of the traits weren't me at all. I laughed at some of the stats of signs regarding people I knew. Yes, I know that some traits are "givens" for the sign, but it was so stereotyped.
The other thing about how Zodiac signs were used was via attraction. Again, it makes sense considering how it is actually used by people to feel out if they could be compatible with someone else. Nevertheless, with the game, if you had two Sims you were set on being together, they could not have the same Zodiac sign. Attraction was not possible for them. Then there was the rest of the system that went into the concept of how certain signs are more compatible and less compatible with each other. That is great for a player just going with the flow, doesn't care to interfere much with their Sims' lives, likes to observe what happens and hopes for some chaos. It is not so great when a player is trying to relive, recreate or create a "new chapter" based on people they know IRL or fictional characters they like.
As it goes, you can just ignore the sign as an actual representation and consider it a silly label rather than actual representation. Flexibility is often a good thing. Nevertheless, what is the point of using the signs as indicators then?
I wouldn't mind the Zodiac signs coming to play as long as they don't create roadblocks. If they affect attraction to some degree, okay... but don't make it impossible for Sims with "grossly incompatible" signs near impossible to be together or Sims with the same sign have no possible attraction for one another.